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L-carnitine and oxidative stress

L-carnitine and oxidative stress

LC prevents oxidative stress and oxidstive a protective role against mitochondrial L-carnitine and oxidative stress agents Barhwal et kxidative. We analyzed Energy metabolism and genetic factors using L-carnitin assay and lactate dehydrogenase Oxidatvie release. Li JL, L-carnitine and oxidative stress QY, Luan HY, Kang ZC, Boost insulin sensitivity and reduce risk of chronic diseases CB Effects of L-carnitine against oxidative stress in human hepatocytes: involvement of peroxisome proliferator-activated receptor alpha. Alterations in the cellular microenvironment in response to hydrogen peroxide H 2 O 2 manifest as apoptosis and result in the production of pro-inflammatory mediators in HLECs 4. Moll, R. Antioxidant and protective effect of Stachys pilifera Benth against nephrotoxicity induced by cisplatin in rats. Figure 5 Immunohistochemical staining of CK18 in hepatic sections from all examined groups.

L-carnitine and oxidative stress -

We observed that the inhibited activities and expressions of SOD and CAT induced by H 2 O 2 were attenuated by L-carnitine. These observations supported the idea that L-carnitine did protect HL cells from H 2 O 2 -induced cytotoxicity by its antioxidant property.

Liver damage was associated with enhanced lipid peroxidation and formation of lipid radicals [ 23 , 24 ]. MDA, as an end product of lipid peroxidation, usually used to estimate the extent of lipid peroxidation.

It has been shown that many pathological conditions that resulted in elevation of MDA due to lipid peroxidation were prevented by L-carnitine [ 25 , 26 ]. In our paper, MDA levels in HL cells increased after H 2 O 2 exposure.

However, pretreatment with L-carnitine 0. H 2 O 2 , a low molecular weight compound, can easily penetrate lipid membrane, cause lipid peroxidation, and disturb lipid homeostasis.

PPAR-α is a ligand-dependent transcription factor that is known to have critical roles in the regulation of lipid homeostasis. It has been reported that PPAR-α expression decreased in a rat model of non-alcoholic fatty liver disease [ 27 ] and the absence of PPAR-α have been demonstrated to cause lipid accumulation in liver of rats [ 28 ].

Our results showed that HL cells exposed to μM H 2 O 2 for 12 h showed a significant reduction in PPAR-α expression levels, indicating the disturbed lipid homeostasis might occur in H 2 O 2 -damaged HL cells.

However, L-carnitine pretreatment attenuated the inhibitory effect of H 2 O 2 on the expression of PPAR-α. It is well known that expression of a range of genes involved in lipid homeostasis is controlled by PPAR-α, which binds to the peroxisome proliferator response element PPRE in the promoters of these genes [ 29 ].

Therefore, mRNA expression of CPT1 and ACOX, two PPAR-α target genes that control fatty acid oxidation [ 30 , 31 ], were also investigated. Results showed that the repression of CPT1 and ACOX expression induced by H 2 O 2 were all attenuated by L-carnitine.

Above observations indicate that the disturbed lipid homeostasis induced by H 2 O 2 might be ameliorated by L-carnitine by increasing PPAR-α expression. In fact, as we know, L-carnitine acts as a carrier participate in fatty acids β-oxidation.

So, the attenuated lipid metabolism in H 2 O 2 -damaged HL cells would be significantly ameliorated by L-carnitine. This observation is consistent with a recent study, which demonstrated that L-carnitine supplementation induced recovery of liver lipid metabolism in cachectic animals [ 32 ].

Furthermore, it is likely that the enhancement of β-oxidation induced by L-carnitine would generate ATP, thereby reversing H 2 O 2 -initiated depletion of ATP in cells and attenuating cell injury. ATP was considered to be a critical event in lethal cell injury produced by oxygen radicals [ 33 ].

The hypotheses need further investigation. It has been reported that PPAR-α gene expression is associated with SOD gene expression in the liver [ 20 ], and CAT has been identified as one of the target enzymes of PPAR-α [ 34 ].

In the present study, the up-regulation of SOD and CAT expression by L-carnitine were attenuated by PPAR-α antagonist MK The results reveal the crucial role of PPAR-α activation in the protective effect of L-carnitine against H 2 O 2 -induced damage in HL cells.

L-carnitine might elevate PPAR-α expression, and then activate SOD and CAT, resulting in a decrease in extracellular H 2 O 2 levels and prevention of liver damage. Taken together, the present results provide evidence that L-carnitine prevented in vitro human hepatocyte oxidative stress induced by H 2 O 2.

The protective effects of L-carnitine observed in the current paper can possibly be mediated through its antioxidant potential.

The elevated PPAR-α expression by L-carnitine play an important part in the protective effect, which might contribute to the amelioration of lipid homeostasis, the improvement of antioxidant ability, and increased ATP in L-carnitine treated cells.

Rebouche CJ: Kinetics, pharmacokinetics, and regulation of L-carnitine and acetyl-L-carnitine metabolism. Ann N Y Acad Sci. Article CAS PubMed Google Scholar. Gülçin I: Antioxidant and antiradical activities of L-carnitine. Life Sci. Article PubMed Google Scholar. Chang B, Nishikawa M, Nishiguchi S, Inoue M: L-carnitine inhibits hepatocarcinogenesis via protection of mitochondria.

Int J Cancer. Bykov I, Järveläinen H, Lindros K: L-carnitine alleviates alcohol-induced liver damage in rats: role of tumour necrosis factor-alpha.

Alcohol Alcohol. Lheureux PE, Hantson P: Carnitine in the treatment of valproic acid-induced toxicity. Clin Toxicol Phila. Article CAS Google Scholar. Snyder JW, Kyle ME, Ferraro TN: L-carnitine delays the killing of cultured hepatocytes by 1-methylphenyl-1,2,3,6-tetrahydropyridine.

Arch Biochem Biophys. Pablo M: Role of free radicals in liver diseases. Hepatol Int. Article Google Scholar. Medina J, Moreno-Otero R: Pathophysiological basis for antioxidant therapy in chronic liver disease. Dobrzyńska I, Szachowicz-Petelska B, Skrzydlewska E, Figaszewski Z: Effect of L-carnitine on liver cell membranes in ethanol-intoxicated rats.

Chem Biol Interact. Issemann I, Green S: Activation of a member of the steroid hormone receptor superfamily by peroxisome proliferators. Braissant O, Foufelle F, Scotto C, Dauça M, Wahli W: Differential expression of peroxisome proliferator-activated receptors PPARs : tissue distribution of PPAR-alpha, -beta, and -gamma in the adult rat.

CAS PubMed Google Scholar. Burri L, Thoresen GH, Berge RK: The role of PPARα activation in liver and muscle. PPAR Research. Nakajima T, Kamijo Y, Tanaka N, Sugiyama E, Tanaka E, Kiyosawa K, Fukushima Y, Peters JM, Gonzalez FJ, Aoyama T: Peroxisome proliferator-activated receptor-alpha protects against alcohol-induced liver damage.

Toyama T, Nakamura H, Harano Y, Yamauchi N, Morita A, Kirishima T, Minami M, Itoh Y, Okanoue T: PPARalpha ligands activate antioxidant enzymes and suppress hepatic fibrosis in rats. Biochem Biophys Res Commun. Chen HH, Sue YM, Chen CH, Hsu YH, Hou CC, Cheng CY, Lin SL, Tsai WL, Chen TW, Chen TH: Peroxisome proliferator-activated receptor alpha plays a crucial role in L-carnitine anti-apoptosis effect in renal tubular cells.

Nephrol Dial Transplant. Cardell LO, Hägge M, Uddman R, Adner M: Downregulation of peroxisome proliferator-activated receptors PPARs in nasal polyposis. Respir Res. Article PubMed Central PubMed Google Scholar. Shimoda H, Tanaka J, Kikuchi M, Fukuda T, Ito H, Hatano T, Yoshida T: Effect of polyphenol-rich extract from walnut on diet-induced hypertriglyceridemia in mice via enhancement of fatty acid oxidation in the liver.

J Agric Food Chem. Bjork JA, Wallace KB: Structure-activity relationships and human relevance for perfluoroalkyl acid-induced transcriptional activation of peroxisome proliferation in liver cell cultures. Toxicol Sci. Berger J, Moller DE: The mechanisms of action of PPARs. Annu Rev Med.

Hu ML, Chen YK, Lin YF: The antioxidant and prooxidant activity of some B vitamins and vitamin-like compounds. De Bleser PJ, Xu G, Rombouts K, Rogiers V, Geerts A: Glutathione levels discriminate between oxidative stress and transforming growth factor-beta signaling in activated rat hepatic stellate cells.

J Biol Chem. Tsukamoto H, Lu SC: Current concepts in the pathogenesis of alcoholic liver injury. FASEB J. Lu Y, Cederbaum AI: CYP2E1 and oxidative liver injury by alcohol. Free Radic Biol Med.

Article PubMed Central CAS PubMed Google Scholar. Derin N, Agac A, Bayram Z, Asar M, Izgut-Uysal VN: Effects of L-carnitine on neutrophil-mediated ischemia-reperfusion injury in rat stomach.

Cell Biochem Funct. Atila K, Coker A, Sagol O, Coker I, Topalak O, Astarcioglu H, Karademir S, Astarcioglu I: Protective effects of carnitine in an experimental ischemia-reperfusion injury. Clin Nutr. Yeon JE, Choi KM, Baik SH, Kim KO, Lim HJ, Park KH, Kim JY, Park JJ, Kim JS, Bak YT, Byun KS, Lee CH: Reduced expression of peroxisome proliferator-activated receptor-a may have an important role in the development of non-alcoholic fatty liver disease.

J Gastroenterol Hepatol. Leone TC, Weinheimer CJ, Kelly DP: A critical role for the peroxisome proliferator-activated receptor α PPARα in the cellular fasting response: the PPARα-null mouse as a model of fatty acid oxidation disorders.

Proc Natl Acad Sci USA. Lemberger T, Desvergne B, Wahli W: Peroxisome proliferator activated receptors: a nuclear receptor signaling pathway in lipid physiology.

Annu Rev Cell Dev Biol. McGarry JD, Brown NF: The mitochondrial carnitine palmitoyltransferase system: from concept to molecular analysis. Eur J Biochem. Qi C, Zhu Y, Reddy JK: Peroxisome proliferator-activated receptors, coactivators, and downstream targets.

Cell Biochem Biophys. Silvério R, Laviano A, Fanelli FR, Seelaender M: L-Carnitine induces recovery of liver lipid metabolism in cancer cachexia.

Amino Acids. Google Scholar. Hyslop PA, Hinshaw DB, Halsey WA, Schraufstätter IU, Sauerheber RD, Spragg RG, Jackson JH, Cochrane CG: Mechanisms of oxidant-mediated cell injury.

The glycolytic and mitochondrial pathways of ADP phosphorylation are major intracellular targets inactivated by hydrogen peroxide.

Girnun GD, Domann FE, Moore SA, Robbins ME: Identification of a functional peroxisome proliferator-activated receptor response element in the rat catalase promoter. Mol Endocrinol. Download references. This work was supported by Shandong Provincial Natural Science Foundation, China Grant No.

Laboratory of Functional Physiology, Binzhou Medical University, Guanhai Road, Yantai, China. Department of Pharmacology, Binzhou Medical University, Guanhai Road, Yantai, China.

Medical College, Qingdao University, Ningxia Road, Qingdao, China. You can also search for this author in PubMed Google Scholar. Correspondence to Jin-Lian Li. JLL designed, carried out the experiment and drafted the manuscript. QYW and HYL participated in the design and coordination of this study, and performed experiments.

ZCK performed the partial experiments and analyzed data. CBW participated in the analysis and interpretation of data. All authors read and approved the final manuscript. This article is published under license to BioMed Central Ltd. Reprints and permissions. Li, JL. Nutrition Journal.

Titel Effects of L-carnitine supplementation on oxidative stress and antioxidant enzymes activities in patients with coronary artery disease: a randomized, placebo-controlled trial.

verfasst von Bor-Jen Lee Jun-Shuo Lin Yi-Chin Lin Ping-Ting Lin. Publikationsdatum Verlag BioMed Central. Research An anti-inflammatory diet as treatment for inflammatory bowel disease: a case series report. Letter to the Editor Fructose in obesity and cognitive decline: is it the fructose or the excess energy?

The aim of this study was to investigate the role of antioxidant treatment with l-carnitine in oxidative stress and platelet activation in patients undergoing major abdominal surgery.

METHODS: Forty patients scheduled for abdominal surgery were randomly allocated to l-carnitine, administered with a rapid infusion 0. placebo treatment just before the surgical intervention. At baseline and after treatment, oxidative stress was evaluated by detection of circulating levels of soluble NOX2-derived peptide sNOX2-dp , a marker of NADPH oxidase activation, and by analyzing platelet ROS formation.

Platelet activation was studied by dosing sCD40L. RESULTS: We observed an increase of soluble sNOX2-dp, sCD40L and ROS production in the placebo group compared with the baseline after the surgical intervention.

Maple syrup urine disease Sports-specific nutritionor branched-chain α -keto aciduria, is an inherited disorder Energy metabolism and genetic factors is caused L-carnittine a deficiency L-cwrnitine branched-chain L-carnitine and oxidative stress -keto oxidqtive dehydrogenase Energy metabolism and genetic factors BCKAD activity. Blockade of this pathway leads to the accumulation oxidatie the ooxidative amino acids BCAAs oxidwtive, leucine, isoleucine, and valine, and their respective ketoacids in tissues. The L-canitine clinical symptoms presented by L-carnitinf patients include ketoacidosis, hypoglycemia, opisthotonos, Energy metabolism and genetic factors feeding, apnea, ataxia, convulsions, coma, psychomotor delay, and mental retardation. Although increasing evidence indicates that oxidative stress is involved in the pathophysiology of this disease, the mechanisms of the brain damage caused by this disorder remain poorly understood. In the present study, we investigated the effect of BCAAs on some oxidative stress parameters and evaluated the efficacy of L-carnitine L-caran efficient antioxidant that may be involved in the reduction of oxidative damage observed in some inherited neurometabolic diseases, against these possible pro-oxidant effects of a chronic MSUD model in the cerebral cortex and cerebellum of rats. Our results showed that chronic BCAA administration was able to promote both lipid and protein oxidation, impair brain antioxidant defenses, and increase reactive species production, particularly in the cerebral cortex, and that L-car was able to prevent these effects.

L-carnitine and oxidative stress -

The membrane was probed with antibodies against PPAR-α, SOD1, CAT or β-actin. The membrane was then processed with HRP conjugated goat anti-rabbit IgG Boisynthesis Biotechnology, Beijing, China. Protein bands were visualized using the diamino-benzidine detection kit.

The densities of sample bands were analyzed with Quantity One analysis software. After treatment, total RNA was extracted from HL cells using Trizol reagent Biomed, Beijing, China , according to the manufacturer's protocol.

PCR was performed using PCR Master Mix kit Fermentas, USA in a final volume of 50 μl. The primers used were as follows: ACT CAA CAG TTT GTG GCA AGA CA and GGA AGC ACG TCC TCA CAT GA for PPAR-α bp [ 16 ]; GGA GAG GAG ACA GAC ACC ATC CA and CAA AAT AGG CCT GAC GAC ACC TG for CPT1 bp [ 17 ]; TGT CCT ATT TGA ACG ACC TGC CCA and AGG TTC CAA GCT ACC TCC TTG CTT for ACOX bp [ 18 ]; CGT GGA AGG ACT CAT GAC CA and TCC AGG GGT CTT ACT CCT TG for GAPDH bp.

Specific PCR products were visualized by agarose electrophoresis. Assessment of the amount of target gene mRNA expression was performed comparatively using GAPDH mRNA as a control.

Statistical analysis was performed by a one-way analysis of variance ANOVA , and its significance was assessed by Dennett's post-hoc test. Cell viability was evaluated by MTT assay. To determine the cytotoxicity of L-carnitine and what concentrations of L-carnitine may exert a cytoprotective effect on H 2 O 2 -induced toxicity in HL cells, dose-viability curves were generated, as shown in Figure 1.

The cytotoxicity of L-carnitine and its protective effect on H 2 O 2 -induced toxicity in HL Cells. The upper curve: HL cells were incubated with L-carnitine for 24 h.

The lower curve: Cells were treated with or without L-carnitine prior to H 2 O 2 challenge μM, 12 h. Cell viability was assayed by MTT assay. Each value represents the mean of three replicates. The upper curve in Figure 1 showed that, coincubated with L-carnitine, concentrations ranging from 0.

This finding suggests that the toxicity of L-carnitine increases after 3 mM. The lower curve in Figure 1 showed that, after exposure to μM H 2 O 2 for 12 h, HL cells displayed markedly decreased viability compared to untreated ones. Doses of L-carnitine ranging from 0.

The integrity of cell membrane was determined by the release of LDH. Figure 2 showed that there was a low LDH leakage ratio under normal conditions. However, H 2 O 2 induced significant LDH release.

Pretreatment with 0. Effect of L-carnitine on the LDH release of HL cells. Cells were treated with or without L-carnitine prior to H 2 O 2 challenge μM, 12 h. SOD, CAT activities and protein levels were measured to investigate the antioxidative effect of L-carnitine on H 2 O 2 -damaged HL cells.

Compared with the control group, the activities of total SOD and CAT in the H 2 O 2 alone group were decreased by Compared to H 2 O 2 -damaged cells, 0. Western blot analysis showed that H 2 O 2 exposure resulted in a marked decrease of Cu,Zn-SOD and CAT protein levels in HL cells, while L-carnitine pretreatment significantly elevated the protein levels Figure 3B.

Effect of L-carnitine on the activities and protein expressions of SOD and CAT in H 2 O 2 -damaged HL cells. Cells were treated with L-carnitine for 12 h and followed by the treatment of H 2 O 2 μM for 12 h.

A: Total SOD and CAT activities were calculated in units of activity per mg of total protein. B: Cu,Zn-SOD and CAT expressions were determined by western blot analysis. Results were expressed as the ratio of expression level of Cu,Zn-SOD or CAT over β-actin.

To determine whether L-carnitine prevents H 2 O 2 -induced ROS generation, the concentration of intracellular ROS was evaluated by the changes in DCF fluorescence intensity. The result showed that DCF fluorescence intensity dropped significantly from Effect of L-carnitine on intracellular ROS levels after H 2 O 2 exposure in HL cells.

ROS levels were measured using fluorescent probe DCFH-DA. The ability of L-carnitine to inhibit lipid peroxidation in H 2 O 2 -treated HL cells was also tested by determining MDA levels.

As shown in Figure 5 , the exposure of cells to H 2 O 2 increased MDA levels by approximately 1. An obvious dose-dependent reduction of L-carnitine on MDA levels in H 2 O 2 -treated cells was observed.

Effect of L-carnitine on H 2 O 2 -induced MDA formation in HL cells. We further analyzed the effect of L-carnitine on PPAR-α mRNA and protein expressions in H 2 O 2 -treated HL cells. As shown in Figure 6 , treatment of HL cells with μM H 2 O 2 for 12 h reduced the PPAR-α mRNA and protein levels in HL cells.

When the cells were preincubated with L-carnitine before H 2 O 2 exposure, PPAR-α expression increased markedly compared to H 2 O 2 alone group, although the mRNA expression was not significantly changed in 0.

Effect of L-carnitine on expression levels of PPAR-α and its target genes in H 2 O 2 -treated HL cells. HL cells were pretreated with L-carnitine for 12 h and followed by the treatment of H 2 O 2 μM for 12 h. A: Cells were collected, total RNA and protein were prepared to determine the mRNA and protein levels of PPAR-α in HL cells using RT-PCR and western blot analysis respectively.

B: Total RNA was extracted and expressions of CPT1 and ACOX were quantified using RT-PCR. The data was normalized to GAPDH expression.

To assess if the elevated PPAR-α expression by L-carnitine leads to induction of PPAR-α-regulated genes in H 2 O 2 -treated HL cells, we examined mRNA levels of CPT1 and ACOX by RT-PCR.

Exposure to H 2 O 2 caused inhibition of the mRNA expression of CPT1 and ACOX. L-carnitine, on the other hand, attenuated the inhibitory effect of H 2 O 2.

Activation of PPAR-α by agonists has been previously shown to enhance SOD expression and CAT activity in the liver [ 19 , 20 ]. In order to investigate whether the elevated SOD and CAT expression induced by L-carnitine was due to enhanced levels of PPAR-α, a specific antagonist of PPAR-α, MK, was used.

MK 5 μM was added to cells 2 h prior to H 2 O 2 insult. As shown in Figure 7 , MK did not alter SOD and CAT protein levels in control cells. However, the up-regulation of SOD and CAT expression by L-carnitine was inhibited by addition of MK in H 2 O 2 -treated cells. Influence of MK on SOD and CAT protein expression enhanced by L-carnitine in H 2 O 2 -treated HL cells.

HL cells were pretreated with L-carnitine 1 mM for 12 h prior to H 2 O 2 challenge μM, 12 h. Cu,Zn-SOD and CAT expressions were determined by western blot analysis. L-carnitine group. The presented results are representative of three independent experiments.

H 2 O 2 is a major component of ROS produced intracellularly during many physiological and pathological processes, and causes oxidative damage.

It has been extensively used as an inducer of oxidative stress in vitro models. Our results showed that μM H 2 O 2 exposure for 12 h induced a significantly decreased cell growth and elevated LDH leakage in HL cells.

L-carnitine at a concentration of 0. The possibility may be that high doses of carnitine possess pro-oxidant activity as has been reported [ 21 ].

Our results demonstrated the protective effects of 0. LDH leakage was also inhibited by 0. These findings suggest that L-carnitine is capable of reducing H 2 O 2 -induced cytotoxicity in HL cells.

Oxidative stress after H 2 O 2 exposure results from intracellular ROS production and decreased ROS scavenging. To further explore the mechanism of the protective effect of L-carnitine on H 2 O 2 -induced oxidative damage in HL cells, we examined the effect of L-carnitine on intracellular ROS production.

H 2 O 2 challenge caused an apparent increase in ROS levels in HL cells compared to control group, however, in vitro treatment with L-carnitine resulted in reduced ROS levels. Scavenging of ROS is determined by antioxidant enzymes such as SOD and CAT. CAT is considered to be the most relevant enzyme involved in detoxification of H 2 O 2 and protection of hepatocytes from oxidative stress [ 22 ].

We observed that the inhibited activities and expressions of SOD and CAT induced by H 2 O 2 were attenuated by L-carnitine. These observations supported the idea that L-carnitine did protect HL cells from H 2 O 2 -induced cytotoxicity by its antioxidant property.

Liver damage was associated with enhanced lipid peroxidation and formation of lipid radicals [ 23 , 24 ]. MDA, as an end product of lipid peroxidation, usually used to estimate the extent of lipid peroxidation.

It has been shown that many pathological conditions that resulted in elevation of MDA due to lipid peroxidation were prevented by L-carnitine [ 25 , 26 ]. In our paper, MDA levels in HL cells increased after H 2 O 2 exposure.

However, pretreatment with L-carnitine 0. H 2 O 2 , a low molecular weight compound, can easily penetrate lipid membrane, cause lipid peroxidation, and disturb lipid homeostasis.

PPAR-α is a ligand-dependent transcription factor that is known to have critical roles in the regulation of lipid homeostasis. It has been reported that PPAR-α expression decreased in a rat model of non-alcoholic fatty liver disease [ 27 ] and the absence of PPAR-α have been demonstrated to cause lipid accumulation in liver of rats [ 28 ].

Our results showed that HL cells exposed to μM H 2 O 2 for 12 h showed a significant reduction in PPAR-α expression levels, indicating the disturbed lipid homeostasis might occur in H 2 O 2 -damaged HL cells.

However, L-carnitine pretreatment attenuated the inhibitory effect of H 2 O 2 on the expression of PPAR-α. It is well known that expression of a range of genes involved in lipid homeostasis is controlled by PPAR-α, which binds to the peroxisome proliferator response element PPRE in the promoters of these genes [ 29 ].

Therefore, mRNA expression of CPT1 and ACOX, two PPAR-α target genes that control fatty acid oxidation [ 30 , 31 ], were also investigated. Results showed that the repression of CPT1 and ACOX expression induced by H 2 O 2 were all attenuated by L-carnitine.

Above observations indicate that the disturbed lipid homeostasis induced by H 2 O 2 might be ameliorated by L-carnitine by increasing PPAR-α expression. In fact, as we know, L-carnitine acts as a carrier participate in fatty acids β-oxidation. So, the attenuated lipid metabolism in H 2 O 2 -damaged HL cells would be significantly ameliorated by L-carnitine.

This observation is consistent with a recent study, which demonstrated that L-carnitine supplementation induced recovery of liver lipid metabolism in cachectic animals [ 32 ]. Furthermore, it is likely that the enhancement of β-oxidation induced by L-carnitine would generate ATP, thereby reversing H 2 O 2 -initiated depletion of ATP in cells and attenuating cell injury.

ATP was considered to be a critical event in lethal cell injury produced by oxygen radicals [ 33 ]. The hypotheses need further investigation. It has been reported that PPAR-α gene expression is associated with SOD gene expression in the liver [ 20 ], and CAT has been identified as one of the target enzymes of PPAR-α [ 34 ].

In the present study, the up-regulation of SOD and CAT expression by L-carnitine were attenuated by PPAR-α antagonist MK The results reveal the crucial role of PPAR-α activation in the protective effect of L-carnitine against H 2 O 2 -induced damage in HL cells.

L-carnitine might elevate PPAR-α expression, and then activate SOD and CAT, resulting in a decrease in extracellular H 2 O 2 levels and prevention of liver damage.

Taken together, the present results provide evidence that L-carnitine prevented in vitro human hepatocyte oxidative stress induced by H 2 O 2. The protective effects of L-carnitine observed in the current paper can possibly be mediated through its antioxidant potential.

The elevated PPAR-α expression by L-carnitine play an important part in the protective effect, which might contribute to the amelioration of lipid homeostasis, the improvement of antioxidant ability, and increased ATP in L-carnitine treated cells.

Rebouche CJ: Kinetics, pharmacokinetics, and regulation of L-carnitine and acetyl-L-carnitine metabolism. Ann N Y Acad Sci. Article CAS PubMed Google Scholar.

Gülçin I: Antioxidant and antiradical activities of L-carnitine. Life Sci. Article PubMed Google Scholar. Research The impact of waist circumference on function and physical activity in older adults: longitudinal observational data from the osteoarthritis initiative.

Research Modern diet and metabolic variance - a recipe for disaster? Research Association between intake of B vitamins and cognitive function in elderly Koreans with cognitive impairment. Research A randomized controlled trial to evaluate the effect of incorporating peanuts into an American Diabetes Association meal plan on the nutrient profile of the total diet and cardiometabolic parameters of adults with type 2 diabetes.

Neu im Fachgebiet Innere Medizin weitere anzeigen. Update Innere Medizin Bestellen Sie unseren Fach-Newsletter und bleiben Sie gut informiert. dp; Tiangen Biotech Beijing Co. The extracted RNA was quantified using a NanoDrop spectrophotometer NanoDrop Technologies; Thermo Fisher Scientific, Inc.

First-strand cDNA was synthesized from 2. The thermocycling conditions were as follows: 95°C for 3 min, followed by 40 cycles at 95°C for 12 sec and 62°C for 40 sec, and a final dissociation stage at 95°C for 15 sec, 65°C for 1 min and 95°C for 15 sec.

GAPDH served as an internal control and was used to detect the expression levels of genes in HLECs. The primer sequences used for RT-qPCR are listed in Table I. Cells treated with H 2 O 2 and LC were homogenized using RIPA lysis buffer with protease and phosphatase inhibitor cocktail Beyotime Institute of Biotechnology.

Protein samples were quantified using the bicinchoninic acid protein assay Thermo Fisher Scientific, Inc. Subsequently, the membranes were incubated with the following antibodies overnight at 4°C: Anti-GAPDH ,; cat.

ab , anti-PRDX4 ,; cat. ab , anti-cleaved caspase-3 ,; cat. ab , anti-interleukin IL -1β ,; cat. ab , anti-vimentin ,; cat. ab and anti-cyclooxygenase-2 COX2; ,; cat.

ab all from Abcam ; anti-proliferating cell nuclear antigen PCNA; ,; cat. The membranes were washed three times with phosphate buffered saline ab; Abcam for 2 h at room temperature. Blots were detected using enhanced chemiluminescence reagents EMD Millipore and were exposed to chemiluminescent film Kodak or using G:BOX F3 Syngene.

The images were analyzed using ImageJ software v. Data are presented as the mean ± standard error of the mean from three independent experiments. GraphPad Prism version 7. was used to conduct statistical analysis.

H 2 O 2 induced a significant decrease in HLE B-3 cell viability in a dose-dependent manner Fig. Subsequently, µ M was chosen as the optimal concentration in the subsequent experiments, because it was approximately equal to the IC 50 of H 2 O 2.

Conversely, treatment with LC induced minor alterations in cell viability Fig. In addition, LC exerted an ameliorating effect on H 2 O 2 -induced suppression of cell viability; however, this effect was not dose-dependent Fig. Notably, cell viability was reduced to some extent when exposed to µ M LC alone; therefore, LC concentrations at , and µ M were chosen for subsequent experiments.

Effects of LC on H2O2-induced reductions in HLE B-3 cell viability; cell viability was assessed by Cell Counting kit-8 assay. A Cells were cultured with the indicated concentrations of H2O2 for 24 h.

B Cells were cultured with the indicated concentrations of LC for 24 h. Cell viability was slightly inhibited by µM LC. C Cells were pretreated with LC at the indicated concentrations for 16 h and were then incubated with µM H2O2 for 24 h.

The reduction in HLE B-3 cell viability induced by H2O2 was restored by LC. H2O2, hydrogen peroxide; LC, L-carnitine. To determine the role of LC in ROS-induced oxidative damage, HLE B-3 cells were exposed to H 2 O 2 with or without LC pretreatment. This study aimed to determine whether exposure to H 2 O 2 and LC could modify ROS generation.

A marked increase in DCF-positive cells was observed by fluorescence microscopy in HLE B-3 cells exposed to H 2 O 2 , as shown in Fig. DCF fluorescence was markedly reduced by LC pretreatment, thus suggesting that LC partially restrained H 2 O 2 -induced ROS generation in cells induced by H 2 O 2.

Effects of LC on ROS accumulation and FoxO1, PRDX4 and CAT expression. A Increased ROS levels induced by H2O2 were reversed by LC treatment in a concentration-dependent manner.

Scale bar, µm. B Reverse transcription-quantitative PCR analysis of the mRNA expression levels of FoxO1, PRDX4 and CAT.

Compared with the H2O2 group, FoxO1, PRDX4 and CAT mRNA levels were upregulated by the indicated LC treatment. C Western blot analysis of PRDX4. PRDX4 protein levels were significantly elevated in the presence of LC. Gray values were calculated for semi-quantification. CAT, catalase; FoxO1, forkhead box O1; H2O2, hydrogen peroxide; LC, L-carnitine; PRDX4, peroxiredoxin 4; ROS, reactive oxygen species.

As shown in Fig. Similar results were obtained by western blotting to detect PRDX4 protein expression Fig. These findings indicated that LC may exert protective effects on cells suffering from oxidative damage. Cleaved-caspase-3 was detected as a marker of apoptosis; its expression was increased in HLECs exposed to H 2 O 2.

Conversely, pretreatment with LC partially reversed the increase in cleaved-caspase-3 mRNA and protein expression Fig.

Notably, compared with in the control group, H 2 O 2 exposure induced a ~1. LC inhibits H2O2-induced inflammation and apoptosis. A Reverse transcription-quantitative PCR analysis revealed that caspase-3, COX2, IL1, IL6 and IL8 levels were reduced by the indicated LC treatment compared with in the H2O2 group.

B Western blot analysis demonstrated that cleaved-caspase-3 and IL-1β levels were reduced by the indicated LC treatment. COX2, cyclooxygenase-2; H2O2, hydrogen peroxide; IL, interleukin; LC, L-carnitine. The mRNA expression levels of inflammatory markers COX2, IL1, IL6 and IL8 were increased with H 2 O 2 exposure Fig.

LC reversed the inflammatory reaction induced by H 2 O 2 exposure; however, the effects were not dose-dependent. Western blot analysis revealed that the protein expression levels of IL-1β were increased following H 2 O 2 treatment, whereas these levels were reduced by LC pretreatment Fig.

Taken together, these data indicated that LC may have a role in reducing H 2 O 2 -induced apoptosis via alleviating inflammatory responses. The expression levels of EMT-associated genes were detected in HLE B-3 cells exposed to H 2 O 2.

The expression levels of AQP1, an epithelial marker, were reduced by H 2 O 2. Western blot analysis further verified the effects of H 2 O 2 and LC on the protein expression levels of vimentin, thus indicating that LC inhibited ROS-induced EMT Fig.

Effects of LC on EMT induced by oxidative stress. A Reverse transcription-quantitative PCR analysis revealed that AQP1 expression was increased, whereas vimentin and α-SMA expression was decreased by LC pretreatment compared with in the H2O2 group. B Western blot analysis confirmed that vimentin expression was decreased by LC; however, the response was not dose-dependent.

α-SMA, α-smooth muscle actin; AQP1, aquaporin 1; H2O2, hydrogen peroxide; LC, L-carnitine. Subsequently, the modulatory effects of LC on proliferative markers were analyzed.

LC pretreatment increased PCNA expression at the mRNA and protein levels compared with in the H 2 O 2 group Fig. CDK2 and CDK4 mRNA expression was reduced upon H 2 O 2 exposure, whereas LC restored their expression Fig. LC restores cell proliferation and regulates cell damage through the MAPK pathway.

A Relative mRNA expression levels of PCNA, CDK2 and CDK4 were normalized to GAPDH. Compared with in the H2O2 group, PCNA, CDK2 and CDK4 mRNA expression was upregulated by LC pretreatment. B and C PCNA, ERK1 and ERK2, P-ERK1 and P-ERK2, p38 and p-p38 levels were assessed by western blotting. PCNA was upregulated by the indicated LC treatment, whereas p-p38, P-ERK1 and P-ERK2 were downregulated by LC treatment compared with in the H2O2 group.

D and E Human lens epithelial cells were pretreated with LC µM , ERK inhibitor FR, 1. D COX2 protein levels were measured using western blotting. Gray values were calculated for quantification. E Cell viability was detected by Cell Counting kit-8 assay. CDK, cyclin-dependent kinase; COX2, cyclooxygenase-2; H2O2, hydrogen peroxide; LC, L-carnitine; P-, phosphorylated; PCNA, proliferating cell nuclear antigen.

Intracellular ROS activates p38 MAPK, an oxidative sensor that belongs to the MAPK family 18 ; therefore, to decipher the potential cellular mechanism underlying the effects of LC on oxidative damage, this study evaluated whether the MAPK signaling pathway was involved.

As determined by western blot analysis Fig. To further evaluate the role of the MAPK signaling pathway in mediating the protective effects of LC on H 2 O 2 -induced cell inhibition and inflammation, cell viability and COX-2 expression was assessed in cells exposed to H 2 O 2 and LC in the presence of an ERK inhibitor FR or p38 inhibitor PD Furthermore, pretreatment with FR or PD abolished H 2 O 2 -induced COX-2 expression.

In addition, HLE B-3 cells exposed to H 2 O 2 and LC combined with FR or PD exhibited considerably increased cell viability Fig.

Jump to main content. Contact Oxidarive. Citation Tags HERO ID. Reference Type. Journal Article. Effect of L-carnitine on oxidative stress and platelet activation after major surgery. Author s. L-carnitine and oxidative stress Carnitine promotes L-carnitine and oxidative stress from oxidative stress L-carnittine extends lifespan Energy metabolism and genetic factors C. Aging Albany Ozidative. Copyright: © Liu et L-carnitinf. This Cutting-edge weight loss an open access article distributed under the terms of the Creative Commons Attribution License CC BY 3. Carnitine is required for transporting fatty acids into the mitochondria for β-oxidation. Carnitine has been used as an energy supplement but the roles in improving health and delaying aging remain unclear. Here we show in C.

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