Increased oxidative stress associated with the severity of the liver disease in various forms of hepatitis B virus infection

The effects of glutamine on hepatic ischemia reperfusion injury in rats

AIM

To evaluate the effects of glutamine on the hepatic ischemia reperfusion injury in rats.

METHODS

Thirty rats were divided into three groups as sham (Group 1), control (Group 2), and glutamine(gln) treatment group (Group 3). All rats underwent hepatic ischemia for 45 min followed by 60 min period of reperfusion. Rats were intraperitoneally infused with only 0.9% saline solution in group 2. Rats in group 3 received gln (0.75 g/kg) by intraperitoneal administration, before ischemia and before reperfusion. Blood samples and liver tissues were harvested from the rats, and then the rats were sacrificed. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) levels were determined. Total antioxidant capacity (TAC), catalase (CAT), total oxidative status (TOS), oxidative stress index (OSI) and myeloperoxidase (MPO) in hepatic tissue were measured. Also liver tissue histopathology was evaluated by light microscopy.

RESULTS

The levels of liver enzymes in group 3 were significantly lower than those in the group 2. TAC in liver tissue was significantly higher in group 3 than in group 2. TOS, OSI and MPO in hepatic tissue were significantly lower in group 3 than the group 2. Histological tissue damage was milder in the gln treatment group than that in the control group.

CONCLUSION

Our results suggest that gln treatment protects the rat liver against to hepatic ischemia-reperfusion injury.

The effect on serum myeloperoxidase activity and oxidative status of eradication treatment in patients Helicobacter pylori infected

OBJECTIVES

Myeloperoxidase activity has been investigated after eradication of Helicobacter pylori (H. pylori) in infected patients in previous studies but the results are controversial. The aim of this study was to investigate effect on serum myeloperoxidase activity and oxidative status of eradication treatment in H. pylori-infected patients.

DESIGN AND METHODS

Gastric biopsy specimens were obtained from 30 H. pylori infected patients. Serum myeloperoxidase activity was measured by enzyme-linked immunoassay. Oxidative status was determined using total antioxidant capacity (TAC) and total oxidant status (TOS) measurement and calculation of oxidative stress index (OSI).

RESULTS

After 2 weeks of the eradication treatment, serum myeloperoxidase activity, TOS and OSI values were significantly lower (all; p<0.001), while TAC was significantly higher (p<0.001).

CONCLUSIONS

Our results indicate that eradication treatment in H. pylori-infected patients may affect both oxidative stress and myeloperoxidase activity which is an important biomarker in pathogenesis of atherosclerosis.

Oxidative stress and antioxidants in hepatic pathogenesis

Long term hepatitis B virus (HBV) infection is a major risk factor in pathogenesis of chronic liver diseases, including hepatocellular carcinoma (HCC). The HBV encoded proteins, hepatitis B virus X protein and preS, appear to contribute importantly to the pathogenesis of HCC. Both are associated with oxidative stress, which can damage cellular molecules like lipids, proteins, and DNA during chronic infection. Chronic alcohol use is another important factor that contributes to oxidative stress in the liver. Previous studies reported that treatment with antioxidants, such as curcumin, silymarin, green tea, and vitamins C and E, can protect DNA from damage and regulate liver pathogenesis-related cascades by reducing reactive oxygen species. This review summarizes some of the relationships between oxidative stress and liver pathogenesis, focusing upon HBV and alcohol, and suggests antioxidant therapeutic approaches.

Vitamins B status and antioxidative defense in patients with chronic hepatitis B or hepatitis C virus infection

BACKGROUND & AIMS

The impact of hepatitis B virus (HBV) or hepatitis C virus (HCV) infection upon B vitamins status and antioxidative defense in infected patients was examined.

METHODS

Dietary record and blood levels of B vitamins and oxidative stress-associated biomarkers were determined for 195 healthy controls, 132 HBV, and 114 HCV patients.

RESULTS

HBV-infected patients had significantly higher levels of total cholesterol, free fatty acids (FFA), and lower ghrelin level (p < 0.05); and HCV-infected patients had significantly higher Ishak inflammation score and lactate dehydrogenase activity (p < 0.05). HBV patients had significantly lower red blood cell (RBC) vitamins B(2) and B(6) levels, and HCV infection significantly decreased vitamins B(2,) B(6) and folate levels in RBC and/or plasma (p < 0.05). Correlation coefficients of RBC vitamin B(2) versus serum FFA in HBV patients, RBC vitamins B(2) and B(6) versus HCV RNA and Ishak inflammation score, and plasma vitamin B(6) vs Ishak inflammation score in HCV patients were <-0.5. HBV-infected patients had significantly higher oxidized glutathione level and lower glutathione peroxidase activity (p < 0.05), but HCV patients had significantly lower superoxide dismutase and catalase activities (p < 0.05).

CONCLUSION

HBV or HCV infection enhanced oxidative stress and lowered B vitamins in circulation. In order to avoid other healthy risk, nutrition status should be monitored and limitation or supplementation of certain nutrients might be helpful for HBV- or HCV-infected patients.

Purified micronized flavonoid fraction ameliorates the injury of spleen and ileum secondary to hepatic ischemia-reperfusion in rats

BACKGROUND

Flavonoids have been subjected to considerable investigations due to their antioxidant and anti-inflammatory properties. Yet the effects of flavonoids on the ileum and spleen against hepatic ischemia-reperfusion injury have so far not been addressed.

AIMS

We aimed to investigate whether micronized purified flavonoid fraction (MPFF) protects the ileum and spleen against hepatic ischemia-reperfusion injury.

METHODS

Rats were subjected to hepatic ischemia by clamping the hilar area of the rats for 60 min, followed by 60 min of reperfusion. Rats in the treatment group were treated with MPFF (80 mg/kg/day) by gavage for 3 days before surgery, 30 min prior to ischemia and just before the reperfusion. After the reperfusion period, all rats were sacrificed. Ileal and splenic tissues were taken for histological evaluation and determination of the total antioxidant capacity (TAC), catalase, total oxidant status (TOS), oxidative stress index (OSI) and myeloperoxidase (MPO) levels.

RESULTS

TAC levels in the splenic tissue and intestinal tissue were significantly higher in the treatment group than in the control group (P < 0.01 for both). TOS, OSI, and MPO in splenic tissue (P < 0.01, P < 0.05, and P < 0.05, respectively) and intestinal tissue (P < 0.01, P < 0.01, and P < 0.001, respectively) were significantly lower in the treatment group than in the control group. Histological tissue damage of intestinal tissue was milder in the treatment group than in the control group.

CONCLUSION

The results of this study indicated that MPFF pretreatment significantly limited the injury to the small intestine and spleen induced by hepatic ischemia-reperfusion in rats.

The antioxidant role of oral administration of garlic oil on renal ischemia-reperfusion injury

AIM

In this study we examined the effect of oral application of garlic form [garlic oil (GO)] on rats after renal ischemia-reperfusion (I/R) injury.

MATERIALS AND METHODS

Forty male Wistar albino rats were divided into four groups: control, sham-operated, I/R, and I/R+GO. GO was diluted in water and administered by oral intubation three times each week for 6 weeks. All rats except sham-operated underwent 45 min of bilateral renal ischemia followed by 6 hr of reperfusion. Blood samples and kidney tissues were harvested from the rats, and then rats were killed. Serum urea, creatinine, and cystatin C levels were determined. Total antioxidant capacity (TAC), catalase (CAT), total oxidant status (TOS), oxidative stress index (OSI), myeloperoxidase (MPO), nitrite oxide (NO), and protein carbonyl (PC) levels in kidney tissue and blood were measured. In addition, kidney tissue histopathology was evaluated.

RESULTS

The serum urea, creatinine, and cystatin C levels were significantly higher in I/R group compared to I/R+GO group (p<0.01). The serum and tissue antioxidant markers (TAC, CAT) were significantly lower in I/R group than I/R+GO group (p<0.01). The serum oxidant markers (TOS, MPO, NO, and PC) were significantly higher in I/R group than I/R+GO group (p<0.01). Also oral application of GO was effective in decreasing of tubular necrosis score.

CONCLUSION

Based on the present data, we conclude that increased antioxidants and decreased oxidants modulated by oral application of GO attenuated the renal I/R injury.

Protective effects of Nigella sativa against ischemia-reperfusion injury of kidneys

BACKGROUND

Ischemia-reperfusion, commonly seen in the fields of trauma surgery and renal transplantation, is a major cause of acute kidney injury and is associated with significant morbidity and mortality. The protective effects of Nigella sativa against ischemia-perfusion damage to various organs have been previously documented. However, its protective effects on kidney tissue against ischemia-reperfusion injury are unclear. In this study, we aimed to examine the effect of Nigella sativa in modulating inflammation and apoptosis after renal I/R injury.

MATERIALS AND METHODS

Thirty male Wistar-albino rats were divided into three groups: sham-operated, ischemia-reperfusion, and ischemia-reperfusion + Nigella sativa. Rats in the third group were given Nigella sativa 6 h prior to ischemia-reperfusion and at the beginning of reperfusion. All rats except those in the sham-operated group underwent 45 min of bilateral renal ischemia followed by 45 min of reperfusion. Blood samples and liver tissues were harvested from the rats, and then rats were sacrificed. Serum urea and creatinine levels were determined. Total antioxidant capacity (TAC), catalase (CAT), total oxidant status (TOS), oxidative stress index (OSI), and myeloperoxidase (MPO) in kidney tissue and blood were measured. Kidney tissue histopathology was also evaluated. Results. Nigella sativa was effective in reducing serum urea and creatinine levels as well as decreasing the tubular necrosis score. Nigella sativa treatment significantly reduced OSI and TOS levels and increased TAC levels in both kidney tissue and blood.

CONCLUSION

The observed differences seem to demonstrate the protective effect of Nigella sativa against renal I/R injury in rat kidneys.

The effects of Nigella sativa on bile duct ligation induced-liver injury in rats

Nigella sativa (NS) has been shown to have antioxidant and antiinflammatory activities in different conditions. The goal of this study was to evaluate the effects of NS on cholestatic liver injury in rats. Thirty rats were recruited in the study as follows: Group 1, Bile duct ligation (BDL) (n = 10); Group 2, BDL plus NS (n = 10); and Group 3, Sham (n = 10). Bile duct ligated group received 0.2 mL kg(-1) dose of NS intraperitoneally daily throughout 14 days. Liver damage and cholestasis were determined by the biochemical and the pathologic examination. Data showed a decrease in gamma glutamyl transferase (GGT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) activities of the NS treated rats when compared with BDL group (p < 0.001 for GGT and p < 0.05 for others). The NS treated rats' tissue levels of total oxidant status (TOS), oxidative stress index (OSI), and myeloperoxidase (MPO) were significantly lower than that of the BDL group (p < 0.01 for all). Increases in total antioxidant capacity (TAC) and catalase (CAT) levels were statistically significant in the NS treated rats compared to BDL group (p < 0.01 for both). On the other hand, administration of NS in the rats with biliary obstruction resulted in inhibition of necro-inflammation. These results indicate that NS exerts a therapeutic effect on cholestatic liver injury in bile duct ligated rats possibly through attenuation of enhanced neutrophil infiltration and oxidative stress in the liver tissue.

Protective effects of resveratrol on small intestines against intestinal ischemia-reperfusion injury in rats

BACKGROUND AND AIM

The aim of this study was to determine whether resveratrol could prevent intestinal tissue injury induced by ischemia-reperfusion (I/R).

METHODS

Intestinal I/R was induced in rats' intestines by 60-min occlusion of the superior mesenteric artery, followed by a 60-min reperfusion. Thirty rats were divided into three groups as follows: sham (group 1), control (group 2), and the treatment groups (group 3). The rats in the treatment group received resveratrol both before ischemia and before reperfusion. In all groups, serum aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase levels were determined. Total antioxidant capacity (TAC), catalase, total oxidative status (TOS), oxidative stress index (OSI), and myeloperoxidase (MPO) in the intestinal tissue were measured. Intestinal tissue histopathology was also evaluated by light microscopy.

RESULTS

The levels of liver enzymes in group 3 were significantly lower than those in group 2 (P < 0.05). TAC in the intestinal tissue was significantly higher in group 3 than in group 2 (P < 0.05). TOS, OSI, and MPO in the intestinal tissue were significantly lower in group 3 than in group 2 (P < 0.05 for all). Histological tissue damage was milder in the resveratrol treatment group than in the control group.

CONCLUSIONS

The results of this study indicated that resveratrol treatment limits the oxidative injury of the small intestine induced by I/R in rats. However, more precise investigations are required to evaluate the antioxidative effect of resveratrol on small intestine tissue damage in clinical and experimental models.

Nigella sativa relieves the deleterious effects of ischemia reperfusion injury on liver

AIM: To determine whether Nigella sativa prevents hepatic ischemia-reperfusion injury to the liver.

METHODS: Thirty rats were divided into three groups as sham (Group 1), control (Group 2), and Nigella sativa (NS) treatment group (Group 3). All rats underwent hepatic ischemia for 45 min followed by 60 min period of reperfusion. Rats were intraperitoneally infused with only 0.9% saline solution in group 2. Rats in group 3 received NS (0.2 mL/kg) intraperitoneally, before ischemia and before reperfusion. Blood samples and liver tissues were harvested from the rats, and then the rats were sacrificed. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) levels were determined. Total antioxidant capacity (TAC), catalase (CAT), total oxidative status (TOS), oxidative stress index (OSI) and myeloperoxidase (MPO) in hepatic tissue were measured. Also liver tissue histopathology was evaluated by light microscopy.

RESULTS: The levels of liver enzymes in group 3 were significantly lower than those in the group 2. TAC in liver tissue was significantly higher in group 3 than in group 2. TOS, OSI and MPO in hepatic tissue were significantly lower in group 3 than the group 2. Histological tissue damage was milder in the NS treatment group than that in the control group.

CONCLUSION: Our results suggest that Nigella sativa treatment protects the rat liver against to hepatic ischemia-reperfusion injury.

Vitamin E in chronic liver diseases and liver fibrosis

Liver fibrosis may be considered as a dynamic and integrated cellular response to chronic liver injury. The activation of hepatic stellate cells and the consequent deposition of large amounts of extracellular matrix play a major role in the fibrogenic process, but it has been shown that other cellular components of the liver are also involved. Although the pathogenesis of liver damage usually depends on the underlying disease, oxidative damage of biologically relevant molecules might represent a common link between different forms of chronic liver injury and hepatic fibrosis. In fact, oxidative stress-related molecules may act as mediators able to modulate all the events involved in the progression of liver fibrosis. In addition, chronic liver diseases are often associated with decreased antioxidant defenses. Although vitamin E levels have been shown to be decreased in chronic liver diseases of different etiology, the role of vitamin E supplementation in these clinical conditions is still controversial. In fact, the increased serum levels of alpha-tocopherol following vitamin E supplementation not always result in a protective effect on liver damage. In addition, clinical trials have usually been performed in small cohorts of patients, thus making definitive conclusions impossible. At present, treatment with vitamin E or other antioxidant compounds could be proposed for nonalcoholic fatty liver disease (NAFLD), the most frequent hepatic lesion in western countries which can progress to nonalcoholic steatohepatitis and cirrhosis due to the production of large amounts of oxidative stress products. However, although some studies have shown encouraging results, multicentric and long-term clinical trials are needed.

Serum prolidase activity and oxidative status in Helicobacter pylori infection

OBJECTIVES

During the course of Helicobacter pylori infection, increased oxidative stress plays an important role in the pathogenesis of gastroduodenal mucosal inflammation, which can cause gastric mucosal atrophy that characterized by the replacement of the gastric mucosal glands by collagen fibers. In the present study, we aimed to determine serum prolidase activity and oxidative status, and to find out if there is any association between serum prolidase activity and oxidative status in H. pylori infection.

DESIGN AND METHODS

Forty H. pylori-positive and 32 H. pylori-negative subjects were enrolled. Serum prolidase activity was measured spectrophotometrically. Oxidative status was determined using total antioxidant capacity and total oxidant status measurement and calculation of oxidative stress index.

RESULTS

Total antioxidant capacity level was lower in H. pylori-positive group than H. pylori-negative group (p<0.001), whereas total oxidant status, oxidative stress index and prolidase activity were higher (all p<0.05). Significant correlation was observed between serum prolidase activity, and total antioxidant capacity, total oxidant status and oxidative stress index (p<0.01, r=-0.367; p<0.05, r=0.283; p<0.01, r=0.379; respectively) in H. pylori-positive subjects.

CONCLUSION

H. pylori infection may be associated with increased oxidative stress and increased serum prolidase activity. Increased oxidative stress seems to be associated with increased serum prolidase activity and this association may help to provide a better understanding about the pathogenesis of H. pylori infection.