Investigation of Dose-Dependent Tissue Protective Effects of Vitamin C

Aim: Vitamin C is an excellent antioxidant in biological systems. However, It is also widely used as a pro-oxidant. This paradoxical behavior results because it is an excellent reducing agent. As for carbon tetrachloride, the incidence of carbon tetrachloride-induced hepatotoxicity is reported to be on the increase. In this study, it is aimed to test, whether additional intake of different concentrations of vitamin C improves antioxidative protection on lipid peroxidation, alanine transaminase, aspartate transaminase, glutathione and protein oxidation levels in single dose carbon tetrachloride-treated male Wistar rats. Material and Method: Two control groups and four treatment groups totaly sixty Wistar albino rats were used in this study. The control groups were fed via oral route a placebo (4 ml of distilled water), while test groups 100 mg /kg, 200 mg/kg, 400 mg/kg and 800 mg/kg body weight of vitamin C in 4ml of distilled water was given via gastric intubation. Results: The administration of vitamin C for 40 days produced a significant decrease with increasing concentrations from 100 to 400 mg/kg of vitamin C in differnt parameters carbon tetrachloride-treated rats. But, the same protection was not observed at higher concentration of vitamin C. Moreover, it has showed hazardous activity at 800 mg/kg concentration as much as carbon tetrachloride-induced toxicity. Discussion: These results showed that vitamin C had not the potential to be used as tissue protective agent at higher doses. Also, results suggest that the same substannces that optimizes antioxidant capacity may also act as prooxidant dependent on its concentration.