Protective effects of N-acetylcysteine and Ginkgo biloba extract on ischaemia-reperfusion-induced hepatic DNA damage in rats

Hepatic ischaemia-reperfusion injury is a serious problem that occurs during various surgical operations such as liver transplantation, surgical revascularization, and partial organ resection. Different pharmacological agents have been used for the protection of organ function and for extending the tolerable ischaemic interval after the ischaemic insult. We aimed to determine the presence of 8-hydroxydeoxyguanosine (8-OHdG) in the DNA from liver undergoing ischaemia-reperfusion, and also to evaluate the protective effects of N-acetylcysteine (NAC) and EGb761 (Ginkgo biloba extract) against hepatic oxidative DNA damage. A total of 40 rats were divided into four groups of 10 animals each (sham-operation group, control group, NAC group, and EGb761 group). Oxidative damage to DNA was evaluated by measuring the increase in 8-OHdG formation in liver tissue and also the effects of NAC and EGb761 pretreatment. Hepatic ischaemia for 90 min followed by reperfusion caused a marked increase in tissue levels of 8-OHdG, thiobarbituric acid-reactive substance, serum ALT, AST and LDH activities compared to sham-operated group. Pretreatment with both NAC and EGb761 clearly diminished 8-OHdG formation and lipid peroxidation. These findings suggest that antioxidant molecules such as NAC and EGb761 may be useful in preventing postischaemic reperfusion injury in hepatic tissue.