Role of L-carnitine in the prevention of acute liver damage induced by carbon tetrachloride in rats

L-carnitine Attenuates DNA Damage and Oxidative Stress in Diabetic Animals

Background: Diabetes is a metabolic disorder characterized by high plasma glucose levels. In this disease, increased production of reactive oxygen species (ROS) results in DNA damage and multiple complications. L-carnitine (LC) has shown a potent antioxidant activity that may reduce oxidative stress. Objectives: This study aims at assaying the effect of LC on DNA damage in streptozotocin-induced diabetic rats and evaluating the changes in antioxidant markers and liver function enzymes after the administration of LC . Methods: In the present study, for induction of diabetes, we injected a single dose of streptozotocin (65 mg/kg) by the intraperitoneal route, and diabetic rats were treated with LC 200, 300, and 400 mg/kg daily for 3 weeks. We detected the DNA damage at 7, 14, and 21 days after induction diabetes by the comet assay method. The blood glucose level, plasma alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were tested. Also, we measured the activity levels of superoxide dismutase (SOD) and intracellular glutathione (GSH). Results: The results of this study demonstrated the increasing amount of DNA damage with the amount and duration of hyperglycemia. L-carnitine treatment significantly decreased the parameters of genotoxicity such as % DNA in the tail, tail length, and tail moment over time. Moreover, the treatment of diabetic rats with LC 300 and 400 mg/kg/day after 21 days led to a remarkable decrease in blood glucose than diabetic rats. Also, we observed that LC can ameliorate enzyme liver function and reduce oxidative stress via enhancement of GSH and SOD levels. Conclusions: The results of this study indicated the protective effect of LC against DNA damage and oxidative stress in diabetic rats.

Besifovir therapy improves hepatic histology and reduces covalently closed circular DNA in chronic hepatitis B patients

BACKGROUND AND AIM

Besifovir dipivoxil maleate (BSV) was reported to have comparable antiviral efficacy and superior renal and bone safety to tenofovir disoproxil fumarate (TDF) in chronic hepatitis B (CHB) patients. The present study aims to evaluate changes of liver histology and intrahepatic covalently closed circular DNA (cccDNA) levels by BSV treatment in comparison with TDF therapy.

METHODS

This is a subset study of the phase 3 trial comparing BSV with TDF. Among them, only CHB patients willing to participate in a histologic evaluation study were enrolled. Liver histologic examination and intrahepatic cccDNA quantification were performed.

RESULTS

A total of 46 CHB patients received liver biopsies (BSV, n = 29; TDF, n = 17). After 48 weeks of treatment, virological response rate was comparable between the groups (P = 0.707). Follow-up liver biopsies showed that necroinflammation was significantly improved in the both groups. However, the histological response rate defined as the proportion of subjects whose modified histologic activity index score decreased by ≥ 2 without deterioration in fibrosis was higher in the BSV group than in the TDF group (77.8% vs 36.4%, P = 0.048). The proportion of subjects with Ishak fibrosis score 3 or more decreased from 77.7% to 55.5% in the BSV and that decreased from 72.7% to 45.4% in the TDF group. The intrahepatic cccDNA significantly decreased from baseline after 48 weeks of BSV or TDF treatment (P < 0.001) without intergroup differences (P = 0.349).

CONCLUSIONS

The BSV therapy improves hepatic histology and decreases intrahepatic cccDNA in CHB patients.

Sialoglycoproteins isolated from the eggs of Carassius auratus alleviates CCL4-induced liver injury via downregulation of the IRE-α/NF-κB signaling pathway

Chemical liver injury is a common cause of liver disease primarily characterized by oxidative stress and inflammation. Sialoglycoproteins isolated from the eggs of Carassius auratus (Ca-SGP) have been proved to exhibit the antioxidant effect. However, the effect of Ca-SGP on liver injury remains unclear. Thus, this study was aimed to determine the effect of Ca-SGP on CCL4-induced chronic chemical liver injury and explore the underlying molecular mechanism. Results showed that Ca-SGP mitigated the elevated levels of serum alanine aminotransferase and aspartate aminotransferase, inhibited the systemic oxidative stress, and reduced the levels of pro-inflammatory factors TNF-α and IL-1β. Histologic results showed that Ca-SGP supplements alleviated hepatocyte necrosis and liver macrophage infiltration. Further, Ca-SGP supplement decreased endoplasmic reticulum stress-related proteins expression, including BiP, IRE-α, p-IRE-α, and TRAF2, and further inhibited the trigger of the NF-κB pathway. In summary, Ca-SGP might be a novel agent for liver injury treatment, and its potential mechanism was related to the inhibition of liver inflammation induced by the endoplasmic reticulum. PRACTICAL APPLICATION: The fish egg is an important by-product in fish processing. Carassius auratus is a common freshwater fish with large catches and low prices. However, the eggs of C. auratus are usually direct discard or processed into salted roe products, and the quality and value of these salted products are unsatisfactory. In this current study, we confirmed that sialoglycoproteins isolated from the C. auratus eggs have the potential for the treatment of liver injury and determined that its mechanism is related to the endoplasmic reticulum and inflammation, which put forward a new idea for solving the by-product of fish processing.

Dietary l-carnitine prevents histopathological changes in tilapia (Oreochromis Niloticus) exposed to cylindrospermopsin

Cylindrospermopsin (CYN) is a cytotoxin highly water-soluble, which is easily taken up by several aquatic organisms. CYN acts as a potent protein and glutathione synthesis inhibitor, as well as inducing genotoxicity, oxidative stress, and histopathological alterations. This is the first study reporting the protective effect of a l-carnitine (LC) pretreatment (400 or 880 mg LC/kg bw fish/day, for 21 days) on the histopathological alterations induced by pure CYN or Aphanizomenon ovalisporum lyophilized cells (400 µg CYN/kg bw fish) in liver, kidney, heart, intestines, and gills of tilapia (Oreochromis niloticus) acutely exposed to the toxin by oral route. The main histopathological changes induced by CYN were disorganized parenchyma with presence of glycogen and lipids in the cytoplasm (liver), glomerulonephritis, glomerular atrophy, and dilatation of Bowman's capsule (kidney), myofibrolysis, loss of myofibrils, with edema and hemorrhage (heart), intestinal villi with necrotic enterocytes and partial loss of microvilli (gastrointestinal tract), and hyperemia and hemorrhage (gills). LC pretreatment was able to totally prevent those CYN-induced alterations from 400 mg LC/kg bw fish/day in almost all organs, except in the heart, where 880 mg LC/kg bw fish/day were needed. In addition, the morphometric study indicated that LC managed to recover totally the affectation in the cross sections of the proximal and distal convoluted tubules in CYN-exposed fish. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 241-254, 2017.

Potential effects of samsum ant, Brachyponera sennaarensis, venom on TNF-α/NF-κB mediated inflammation in CCL4-toxicity in vivo

Background

Ant venom shows antimicrobial, anti-parasitic and anti-inflammatory activities, both in vitro and in vivo. Our recent studies have confirmed the role of samsum ant venom (SAV) as a powerful antioxidant. This study aimed to investigate whether SAV as a potential treatment for CCl4-induced acute liver toxicity in an animal (rat) model.

Methods

Thirty-two rats were assigned into four groups; the first one served as the control. The second group received a single dose of 1 ml/kg CCl₄ in a 1:1 ratio with olive oil through an intraperitoneal injection. The third group received a single dose of 1 ml/kg CCl₄ and then treated with SAV at a dose of 100 μg SAV twice a week for three weeks. The fourth group received a dose of 100 μg SAV only twice a week for three weeks. ELISA, RT-PCR and histopathological examinations were applied.

Results

Results showed that antioxidant enzymes were significantly reduced in the diseased animals. SAV was found to significantly restore the oxidative stability in diseased animals. ELISA estimation and RT-PCR analysis also showed significant upregulation of both nuclear factor (κB) NF-κB and inhibitor (κB) IκB, respectively, in the diseased animals compared to the normal ones. The expression of tumour necrosis factor alpha (TNF-α) and pro-apoptotic receptor (Fas) were also significantly up-regulated in the diseased rats. Interestingly, SAV was found to significantly restore NF-κB, IκB and TNF-α in the diseased rats to the normal values. As a result, liver enzymes, serum proteins and lipid concentrations were significantly improved by SAV in CCl4-animals in comparison with the control ones. Moreover, SAV obviously improved the hepatic tissues of the same group was.

Conclusion

SAV treatment restores the normal biochemical and oxidative stability by improving the TNF-α/NF-κB mediated inflammation in CCL4-treated rats.

Protective effect of L-carnitine in cyclophosphamide-induced germ cell apoptosis

Cyclophosphamide (CP) is a widely used anti-cancer agent; however, it can also induce serious male infertility. There are currently no effective drugs to alleviate this side-effect. L-Carnitine has been used to treat male infertility, but whether it can be used to protect against CP-induced male infertility is still unclear. This study aims to explore the effect and mechanism of L-carnitine in male infertility induced by CP. CP was used to establish an animal model. After three weeks of treatment, rats were sacrificed and testis and serum were harvested for further evaluation. Testosterone and estrogen levels were measured by enzyme-linked immunosorbent assay (ELISA). Testicular injury was examined by hematoxylin and eosin (H & E) staining, and germ-cell apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). The expression of LC3 and Beclin-1 was examined by immunohistochemistry, Western blot, and real-time polymerase chain reaction (PCR), respectively. Compared with the CP group, L-carnitine significantly increases sperm motility, viability, and testosterone level (P<0.05). Western blot and real-time PCR results showed that L-carnitine treatment can significantly up-regulate the LC3-II and Beclin-1 expression in the CP+L-carnitine group when compared with the control group (P<0.05). In addition, TUNEL-positive cells were also more numerous in the CP group; however, L-carnitine can effectively retard cell apoptosis in the CP+L-carnitine group. In conclusion, L-carnitine contributes to the inhibition of cell apoptosis and the modulation of autophagy in protecting CP-induced testicular injury. These results suggest the applicability of L-carnitine in the treatment of male infertility.

Biochemical and biomechanical assessment of effects of L-carnitine on oral mucosal wounds

OBJECTIVES

The present study aimed to investigate the oral mucosal wound healing potential of L-carnitine in a rat model.

MATERIALS AND METHODS

Twenty-four Wistar-albino rats were divided into 4 groups: control group (group I), L-carnitine groups (100 and 200 mg/kg/day, intraperitoneally) (groups II and III), and vitamin E group (100 mg/kg/day, intraperitoneally) (group IV). A 1.5-cm linear incision was created on the buccal mucosa of each rat and was left to heal by secondary intention. On the tenth day, rats were anesthetized and sacrificed. The tensile strength of wound was measured with a tensiometer. Hydroxyproline (HYP) and malondialdehyde (MDA) levels in wound were assayed by spectrophotometry. Results were statistically analyzed using a one-way ANOVA analysis (p ≤ 0.001).

RESULTS

In the analysis of tissue samples, there was a statistically significant decrease in MDA levels in group II (p < 0.01) and group IV (p < 0.001). Wound tension strength that was seen in groups II (57.88 %) and IV (48.71 %) was better than group III (33.39 %). Hydroxyproline levels in group II (46.98 ± 1.37) was higher than groups III (29.40 ± 1.64) and IV (38.83 ± 1.41).

CONCLUSION

Although there was a tendency toward faster healing in the groups receiving L-carnitine, it may have a dose-related positive effect for wound healing.

CLINICAL RELEVANCE

With the advantages of having positive effects on wound healing, being a natural substance in the body, being easy to procure, and having a practical usage, L-carnitine may be clinically feasible for human oral mucosal wounds.

Reversing effects of lignans on CCl4-induced hepatic CYP450 down regulation by attenuating oxidative stress

Oxidative stress has been proved to be a critical reason of regulating CYP450s under hepatic injury status. The study was aimed to investigate the effect of pretreatment of schisandra lignan extracts (SLE) and dimethyl diphenyl bicarboxylate (DDB) on expressions and activities of the main liver P450 isoenzymes in CCl4 induced liver injury rats and their anti-oxidative effects on both CCl4 induced liver injury rats and a CCl4 induced HepG2 cell injury model. Acute experimental liver injury induced by CCl4 caused drastically decreasing activities of the main liver P450 isoenzymes such as CYP1A2, CYP2C6, CYP2E1 and CYP3A2, as well as their protein expressions. Pretreatment of SLE (500 mg/kg) and DDB (200 mg/kg) twice a day for three days significantly decreased the losses of activities of CYP1A2, CYP2C6, CYP2E1 and CYP3A2. Similar results were observed in protein expressions. In addition, in the CCl4 induced HepG2 cells injury model and the CYP3A activity level correlated well with ROS level in several ingredients of SLE treated groups, especially in γ-schisandrin group. These results indicated that the reversion of P450 after SLE/DDB treatment were, on one hand, due to hepatoprotective effects of these lignans on livers; on the other hand, due to their regulation of P450 through anti-oxidative effect and γ-schisandrin might be the most powerful ingredient of SLE. Also, there might be potential interactions between SLE or DDB and co-administered medicines and it is necessary to adjust the dosage of co-administrated medicines in clinical medication of liver disease.

The effects of exogenous l-carnitine on lipid peroxidation and tissue damage in an experimental warm hepatic ischemia-reperfusion injury model

BACKGROUND

l-Carnitine is the essential endogenous factor for the transport of long-chain fatty acids from the cytoplasm to within the mitochondrion where the β-oxidation process takes place. l-Carnitine is a superoxide scavenger and an antioxidant that possesses an anti-ischemic action and a stabilizing effect on cell membranes. It may be of help in liver ischemia reperfusion injury. RESULTS regarding the effects of l-carnitine on liver ischemia and reperfusion injury are few and conflicting.

OBJECTIVE

The aim of this study was to investigate the efficacy of exogenous l-carnitine on lipid peroxidation and protecting liver at different stages of experimental total warm hepatic ischemia-reperfusion (TWHIR) procedure in rats.

METHODS

This experimental study in healthy, weanling, male Wistar rats (weighing 180-200 g) was conducted at the Experimental Animal Research Laboratory of the Faculty of Medicine of Mersin University, Mersin, Turkey. Rats were randomly divided into 5 groups: (A) Control group; (B) TWHIR procedure only; (C) l-carnitine administered 2 hours before the TWHIR procedure; (D) l-carnitine administered just before the TWHIR procedure; and (E) l-carnitine administered after total warm hepatic ischemia but just before the reperfusion procedure. Total warm hepatic ischemia (via the Pringle maneuver) and reperfusion were performed for 45 and 30 minutes, respectively. l-Carnitine (200 mg/kg) was administered intravenously. At the end of each procedure a blood sample was drawn and total hepatectomy was performed following reperfusion. Malondialdehyde (MDA) and myeloperoxidase (MPO) levels of both plasma and liver tissue, total antioxidant capacity (TAOC), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in plasma, and histopathologic examination were analyzed to assess lipid peroxidation and damage in liver tissue.

RESULTS

Thirty-four rats (mean [SD]age, 59.26 [1.2]days; mean [SD] weight, 194.1 [5.1] g) were used in the study. There was a significant difference observed between groups A (n = 5) and B (n = 5) for all evaluation parameters. The TWHIR procedure performed in group B was associated with significant increases versus baseline in ALT, AST, MDA, and MPO in plasma, and MDA and MPO in liver tissue, but a significant decrease of TAOC in plasma. ALT, AST, serum and liver MDA, and MPO levels of group B were significantly higher than all groups administered l-carnitine. l-Carnitine administration between total warm hepatic ischemia and reperfusion was associated with a significant attenuation in all parameters. The liver MDA levels of groups C (n = 8) and D (n = 8) were significantly lower than that of group E (n = 8) (mean [SD]: C, 16.53 [3.32] and D, 18.28 [1.67] vs E, 23.05 [3.52]; P = 0.001 and P = 0.016, respectively). The mean (SD) liver MPO level of group C (1.09 [0.16]) was significantly lower than that of groups D (2.12 [0.25]) and E (2.11 [0.28]) (both, P = 0.001). The TAOC of group B (0.77 [0.12]) was significantly lower than that of groups C (1.34 [0.19]) and D (1.08 [0.20]) (P = 0.001 and P = 0.015, respectively). The TAOC of group C was significantly higher than that of the other l-carnitine groups (E, 0.94 [0.13]) (P = 0.023 vs group D; and P = 0.001 vs group E). Histopathologic scores of groups A, C, and E were significantly lower than that of group B, but the difference between groups B and D was not statistically significant.

CONCLUSIONS

In this experimental study, administration of exogenous l-carnitine was associated with significantly decreased lipid peroxidation in plasma and liver tissue when administered prior to a TWHIR procedure. In addition, l-carnitine seemed to be more effective with regard to decreasing lipid peroxidation in liver tissue when administered before warm hepatic ischemia. l-Carnitine was associated with significantly decreased leukocyte sequestration in plasma and liver tissue. A significant increase in TAOC was associated with l-carnitine administered prior to ischemia. These observations suggest that l-carnitine might have a protective effect against ischemia-reperfusion injury in rat liver tissue.

Protective effects of L-carnitine, N-acetylcysteine and genistein in an experimental model of liver fibrosis

AIM

Liver fibrosis is a reversible wound-healing response that occurs following liver injury. In this study, we aimed to investigate the possible protective effects of L-carnitine, N-acetylcysteine and genistein in liver fibrosis induced by carbon tetrachloride (CCl4). In addition, the effects of these agents were compared in the same study.

METHODS

In this study, rats were randomly allocated into 8 groups, consisting of 10 rats each, as follows: a control group, CCl4, L-carnitine, N-acetylcysteine, genistein, CCl4 and L-carnitine, CCl4 and N-acetylcysteine, and CCl4 and genistein. At the end of 6 weeks, blood and liver tissue specimens were collected. Alanine aminotransferase (ALT); aspartate aminotransferase (AST); complete blood count, tumor necrosis factor-α (TNF-α); platelet-derived growth factor-BB (PDGF-BB); interleukin-6 (IL-6); liver glutathione level; oxidant/antioxidant status; scores of hepatic steatosis, necrosis, inflammation, and fibrosis; and the expression of α-smooth muscle actin were studied.

RESULTS

Although the ALT and AST values in the group administered CCl4 were significantly higher than in all the other groups (P<0.05), there was no significant difference between the control group and the groups administered CCl4 combined with L-carnitine, N-acetylcysteine and genistein (P>0.05). There were significant differences in the levels of TNF-α, PDGF-BB and IL-6 (P<0.05) between the CCl4 group and the groups with L-carnitine, N-acetylcysteine and genistein added to CCl4. N-acetylcysteine and genistein had positive effects on the oxidant/antioxidant status and on liver necrosis and fibrosis scores.

CONCLUSIONS

In our study, L-carnitine, N-acetylcysteine and genistein showed significant protective effects in liver fibrosis induced by CCl4.

Hepatoprotective effect of β-chitosan from gladius of Sepioteuthis lessoniana against carbon tetrachloride-induced oxidative stress in Wistar rats

Chitosan has attracted much attention as a biomedical material, owing to its unique biological activities. In this study, hepatoprotective effect of β-chitosan obtained from the gladius of squid Sepioteuthis lessoniana was studied against carbon tetrachloride (CCl4)-induced oxidative stress and liver injury in rats. The rats that received β-chitosan along with the administration of CCl4 showed significantly decreased plasma and tissue alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities and total cholesterol, triglyceride (TG) and free fatty acid (FFA) contents, whereas the treatment with β-chitosan alone markedly increased rat hepatic and circulatory superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) and reduced glutathione (GSH) levels and decreased the malondialdehyde level. Histopathological observations recommended the marked hepatoprotective effect of β-chitosan. The CCl4-induced alterations on circulatory and hepatic antioxidant defence system were normalised by β-chitosan, and it could be concluded that the hepatoprotective effect of chitosan may be due to its antioxidant and antilipidemic property. Therefore, β-chitosan could be considered as antihepatotoxic agent.

In vitro and in vivo hepatoprotective and antioxidant effects of Astragalus polysaccharides against carbon tetrachloride-induced hepatocyte damage in common carp (Cyprinus carpio)

The present study is aiming at evaluating the hepatoprotective and antioxidant effects of Astragalus polysaccharide (APS) on the carbon tetrachloride (CCl(4))-induced hepatocyte and liver injury in common carp in vitro and in vivo. In vitro, APS (200, 400 and 800 μg/ml) was added to the carp primary hepatocytes before (pre-treatment), after (post-treatment) and both before and after (pre- and post-treatment) the incubation of the hepatocytes with CCl(4) at 8 mM in the culture medium. APS at concentrations of 200, 400 and 800 μg/ml significantly improved cell viability and inhibited the elevation of glutamate pyruvate transaminase (GPT), glutamate oxalate transaminase (GOT), lactate dehydrogenase (LDH) and malondialdehyde (MDA) and significantly increased the reduced level of superoxide dismutase (SOD). In vivo administration of APS at the doses of 1.5 and 3 g/kg in the diet for 60 days prior to CCl(4) intoxication significantly reduced the elevated activities of GPT, GOT and LDH and increased the reduced levels of total protein and albumin in the serum; meanwhile, the reduced levels of SOD, glutathione and total antioxidant capacity (T-AOC) were markedly increased and the MDA formation was significantly inhibited in liver tissue. Overall results proved the hepatoprotective action of APS, which is likely related to its antioxidant activity. The results support the use of APS as a hepatoprotective and antioxidant agent in fish.

Antioxidant potential of Cymbopogon citratus extract: alleviation of carbon tetrachloride-induced hepatic oxidative stress and toxicity

This study was aimed to evaluate the effect of Cymbopogon citratus against carbon tetrachloride (CCl(4))-mediated hepatic oxidative damage in rats. Rats were administrated with C. citratus extract (100, 200 and 300 mg/kg b.w.) for 14 days before the challenge of CCl(4) (1.2 ml/kg b.w. p.o) on 13th and 14th days. Hepatic damage was evaluated by employing serum biochemical parameters (alanine aminotransferase-ALT, aspartate aminotransferase-AST and lactate dehydrogenase-LDH), malondialdehye (MDA) level, reduced GSH and antioxidant enzymes (catalase: CAT, glutathione peroxidase: GPX, quinone reductase: QR, glutathione S-transferase: GST, glutathione reductase: GR, glucose-6-phosphate dehyrogenase: G6PD). In addition, CCl(4)-mediated hepatic damage was further evaluated by histopathological examination. However, most of these changes were alleviated by prophylactic treatment of animals with C. citratus dose dependently (p < 0.05). The protection was further evident through decreased histopathological alterations in liver. The results of the present study indicated that the hepatoprotective effect of C. citratus might be ascribable to its antioxidant and free radical scavenging property.

Hepatoprotective and antioxidant effects of Glycyrrhiza glabra extract against carbon tetrachloride (CCl(4))-induced hepatocyte damage in common carp (Cyprinus carpio)

The present study is aiming at evaluating the hepatoprotective and antioxidant effects of Glycyrrhiza glabra extract (2.5, 5 and 10 μg/ml) on the carbon tetrachloride (CCl(4))-induced carp hepatocyte damage in vitro. Glycyrrhiza glabra extract was added to the carp primary hepatocytes before (pre-treatment), after (post-treatment) and both before and after (pre- and post-treatment) the incubation of the hepatocytes with CCl(4). CCl(4) at 8 mM in the culture medium produced significantly elevated levels of lactate dehydrogenase (LDH), glutamate oxalate transaminase (GOT), glutamate pyruvate transaminase (GPT) and malondialdehyde (MDA) and significantly reduced levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Pre-treatment (5 μg/ml) and pre- and post-treatment (5 and 10 μg/ml) of the hepatocytes with Glycyrrhiza glabra extract significantly reduced the elevated levels of LDH, GOT, GPT and MDA and increased the reduced levels of SOD and GSH-Px by CCl(4); post-treatment of the hepatocytes with Glycyrrhiza glabra extract at 5 μg/ml reduced the GPT and GOT levels and increased the GSH-Px level, but had no effect on the other parameters at all the studied concentrations. The results support the use of Glycyrrhiza glabra extract as a hepatoprotective and antioxidant agent in fish.

Preliminary study comparing the effects of locally and systemically applied L-carnitine on the healing of full-thickness skin defects

BACKGROUND AND AIMS

L-carnitine as an endogenous cofactor has a role in the regulation of energy flow between different oxidative sources. The purpose of this study is to investigate that the clinical and histopathologic effects of L-carnitine locally and systemically on secondary healing in wounds of full thickness defects. We also measured the effects of L-carnitine on wound tensile strength as mechanical.

MATERIAL AND METHODS

sixty adult male Sprague-Dawley rats were divided into three groups randomly; group 1 (control group, n = 20), group 2 (local experimental group, n = 20), group 3 (systemic experimental group, n = 20). Group 1 was not given any pharmacologic agents. L-carnitine was administered locally in the group 2, and systemically in group 3 for a total of 14 days. The healing days of all groups were recorded. On the 7th, 10th,14th and 21st postoperative days, biopsy specimens, including tissue samples both from healing wound sites and sur-rounding healthy skin were evaluated for neovascularization, inflammation, the amount of collagen deposit, fibroblast migration and re-epithelization. Tensile strength was measured in the samples which completed healing on the 30th day. The results were evaluated by nonparametric Kruskall-Wallis test followed by Mann Whitney-U test.

RESULTS

the mean clinical healing days were 18.25 days, 16.5 days, 15 days for the control group, local experimental and systemic group, respectively. The differences between groups were statistically significant (p < 0.005). Mean tensile strength values were 762.10 centinewton (cN), 801.69 cN and 786.13 cN for the control group, local experimental group and systemic experimental group, respectively. There were no statistically significant differences between groups (p > 0.05). There was no statistically significant difference in the histopathologic ex-amination on the 7th, 10th, 14th and 21st days in the neovascularization, inflammation and fibroblast migration. Collagen deposit was most prevalent in the systemic experimental group and was least in the control group. Complete wound closure rate was observed on the 7th day in the systemic administration group, on the 10th day in local administration group and on the 14th day in the control group. Re-epithelization thickness in the systemic carnitine group was more than the other groups.

CONCLUSIONS

L-carnitine administered locally or systemically has positive effects on wound healing rate and tensile strength in rats.

Protective effect of L-carnitine and coenzyme Q10 on CCl₄-induced liver injury in rats

This study provides an information about the mechanisms of liver injury induced by CCl₄, and determines the influence of administration of L-carnitine or/and CoQ10 as prophylactic agents against CCl₄ deteriorative effect. The study was carried out on 80 adult male albino rats divided into eight groups, 10 animals each, as follows: four normal groups (control, treated with L-carnitine, treated with CoQ10, and treated with a combination of Lcarnitine and CoQ10) and four liver injury groups treated with CCl₄ (control, treated with L-carnitine, treated with CoQ10, and treated with a combination of L-carnitine and CoQ10). Liver injury was induced by s.c. injection of a single dose of CCl₄ (1 ml/kg). L-carnitine (50 mg/kg/day) was given i.p. for four successive days 24 hours before CCl₄ injection, and CoQ10 (200 mg/kg) was given as a single i.p. dose 24 hours before CCl₄ injection. Animals were sacrificed 24 hours after CCl₄ injection, blood samples were withdrawn and liver tissue samples were homogenized. The levels of the following parameters were determined: hepatic reduced glutathione, serum ALT and AST, hepatic lipid peroxides, hepatic vitamin C, hepatic and serum total protein, serum albumin, serum sialic acid, serum nitrite, and serum and hepatic total LDH activities and LDH isoenzymes. The obtained data revealed that CCl₄ injection produced a significant decrease in reduced glutathione content, vitamin C, total protein and albumin levels. However, there was a significant increase in serum ALT and AST activities, lipid peroxides, sialic acid, nitric oxide, serum and hepatic total LDH activities. On the other hand, groups treated with L-carnitine or/and CoQ10 prior to CCl₄ injection showed an improvement in most parameters when compared with cirrhotic control group. It has been concluded that L-carnitine and coenzyme Q10 have a pronounced prophylactic effect against liver damage induced by halogenated alkanes such as carbon tetrachloride.

L-Carnitine Protects Human Retinal Pigment Epithelial Cells from Oxidative Damage

PURPOSE

To determine the efficacy of L-carnitine (LC) against oxidative changes in human retinal pigment epithelium (RPE) cells.

METHODS

The RPE cells from human donor eyes were cultured in Hams F-10 medium. The effect of LC on H2O2-induced morphologic changes in the RPE cells was analyzed by light microscopy. Reduction in cell death after the impact of LC treatment on H2O2-treated cells was analyzed by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assays. In addition, the effect of H2O2 on the activity of RPE-antioxidant enzymes, glutathione (GSH) and superoxide dismutase (SOD), and LC-induced protection was also determined.

RESULTS

LC protected the RPE cells by inhibiting the peroxide-induced cytopathic effect from 50% to 10%. Nuclear condensation observed in 40% of the H2O2-treated cells decreased to 20% after LC treatment. The MTT assays demonstrated that 100 microM oxidant caused appreciable cell death, which was reduced by LC treatment; however, 100% protection was not achieved. Significant peroxide-induced cell death was seen within 5 hr of H2O2 treatment, and a quantifiable reduction was observed after LC treatment for a similar time period. The change in the antioxidant potential of the RPE induced by oxidative stress was restored by LC treatment, as demonstrated by an increase in GSH and SOD activities.

CONCLUSIONS

LC is capable of protecting the RPE cells from H2O2-induced oxidative damage, implying that micronutrients can have a positive effect and can play an important role in the treatment of oxidation-induced ocular disorders. Further studies are needed to understand the mechanism of LC-induced protection to the RPE cells.

Inhibition of carbon tetrachloride–mediated apoptosis and oxidative stress by melatonin in experimental liver fibrosis

Melatonin, the principal secretory product of the pineal gland, functions as a potent antioxidant and free radical scavenger. Additionally, the antiapoptotic effect of melatonin has been observed both in vivo and in vitro. The aim of this experimental study was to investigate the protective effects of melatonin against carbon tetrachloride (CCl4)–induced apoptosis and oxidative stress in rat liver. Twenty-four male Wistar rats were divided in three equal groups. Group I was used as control. Rats in group II were injected every other day with CCl4 (0.5 mL/kg BW) for a month, whereas rats in group III were treated every other day with the same dose of CCl4 plus melatonin (25 mg/kg BW). At the end of the experiment, all animals were killed by decapitation and the livers were rapidly removed. Some of the liver tissue specimens were used for determination of malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels. The remaining tissue specimens were processed for immunohistochemical assessment, and the percentage rates of apoptotic liver cells stained with immunoreactive Bax were determined. Chronic administration of CCl4 significantly increased liver MDA contents, as an end product of lipid peroxidation, and also significantly decreased SOD and GSH-Px activities, emphasizing the generation of increased oxidative stress. Moreover, it caused an evident increase in apoptotic cells. Melatonin treatment significantly reduced MDA levels and elevated SOD and GSH-Px activities in rats received CCl4 plus melatonin. Furthermore, apoptotic changes caused by CCl4 were considerably decreased in these animals. The results of the present study indicate that melatonin treatment substantially prevents CCl4-induced apoptosis and oxidative damage in the liver. Thus, melatonin may serve as a drug for treating many clinical conditions that arise from inappropriate apoptosis.

High Doses of Stavudine Induce Fat Wasting and Mild Liver Damage without Impairing Mitochondrial Respiration in Mice

Objective

Stavudine (d4T), a nucleoside reverse-transcriptase inhibitor (NRTI), can induce lipoatrophy, fatty liver, hyperlactataemia and abnormal liver tests. NRTI toxicity is usually ascribed to mitochondrial DNA (mtDNA) depletion and impaired mitochondrial respiration. However, NRTIs could have effects unrelated to mtDNA. Recently, we reported that 100 mg/kg/day of d4T stimulated fatty acid oxidation (FAO) in mouse liver, and reduced body fatness without depleting white adipose tissue (WAT) mtDNA. We hypothesized that higher d4T doses could further reduce adiposity, while inhibiting hepatic FAO.

Methods

Mice were treated for 2 weeks with d4T (500 mg/kg/day), L-carnitine (200 mg/kg/day) or both drugs concomitantly. Body fatness was assessed by dual energy X-ray absorptiometry, and investigations were performed in plasma, liver, muscle and WAT.

Results

D4T reduced the gain of body adiposity, WAT leptin, whole body FAO and plasma ketone bodies, and increased liver triglycerides and plasma aminotransferases with mild ultrastructural abnormalities in hepatocytes. Plasma lactate and respiratory chain activities in tissues were unchanged. Stearoyl-CoA desaturase (SCD-1), an enzyme negatively regulated by leptin, was overexpressed in liver. High doses of β-aminoisobutyric acid (BAIBA), a d4T catabolite, increased plasma ketone bodies. Although L-carnitine did not correct body adiposity, it prevented d4T-induced impairment of FAO and liver abnormalities.

Conclusions

D4T overdosage triggers fat wasting, leptin insufficiency and mild liver damage, without causing respiratory chain dysfunction. Overexpression of SCD-1 reduces fatty acid oxidation and overcomes the stimulating effect of BAIBA on hepatic FAO. L-carnitine does not correct leptin insufficiency but prevents d4T-induced impairment of FAO and liver damage.

Effects of L-carnitine on oxidant/antioxidant status in acetic acid-induced colitis

Recently, the role of oxidative stress in the pathogenesis of ulcerative colitis has been investigated. This study was designed to evaluate the possible beneficial effects of L-carnitine on tissue injury and oxidative stress in acetic acid-induced colitis in rats. Acetic acid administration induced severe damage macroscopically and histopathologically in colon and significantly increased the levels of malondialdehyde and myeloperoxidase in colonic tissue. Supplementation of L-carnitine to acetic acid-treated rats did not prove to induce any improvements in macroscopic scores, while L-carnitine administration improved histopathologic scores and significantly decreased malondialdehyde and myeloperoxidase levels in treatment groups. Acetic acid administration significantly decreased reduced glutathione, superoxide dismutase, and catalase levels in colonic homogenate. Supplementation of L-carnitine prevented the depletion of reduced glutathione levels but significantly increased superoxide dismutase levels. On the other hand, no significant change in catalase activity was observed. In conclusion, these results may reflect that L-carnitine could be beneficial as a complementary agent in treatment of ulcerative colitis.

Protective effects of caffeic acid phenethyl ester (CAPE) on carbon tetrachloride-induced hepatotoxicity in rats

In the present study, protective effects of caffeic acid phenethyl ester (CAPE) have been evaluated on carbon tetrachloride (CCl4)-induced hepatotoxicity in rat. Twenty-four male Wistar rats were divided in three groups. Group I was used as control. Rats in group II were injected every other day with CCl4 for 1 month, whereas rats in group III were injected every other day with CCl4 and CAPE for 1 month. At the end of the experiment, all animals were killed by decapitation and blood samples were obtained. Serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total and conjugated bilirubin levels and hepatic malondialdehyde (MDA) contents were determined. For histopathological evaluation, livers of all rats were removed and processed for light microscopy. All biochemical parameters in serum and the hepatic MDA content were significantly higher in animals treated with CCl4 than in the controls. Rats treated with CCl4 and CAPE showed a significant reduction in biochemical parameters in serum and hepatic MDA content. Livers of rats treated with CCl4 showed classic histology of cirrhosis, whereas the histopathological changes were reduced after administration of CCl4 and CAPE. A normal lobular appearance was observed in livers in this group except for fatty degeneration. The results of our study indicate that CAPE treatment prevents CCl4-induced liver damage in rats.