RADIATION-INDUCED OXIDATIVE DAMAGE ON COLLAGEN MOLECULE AND PROTECTIVE EFFECTS OF N-ACETYLCYSTEINE IN GUINEA PIGS LIVER

摘要

The main biological effects of radiation are mediated by short-lived and very reactive chemical molecules called free radicals. Free radicals can oxidatively damage biological macromolecules such as DNA, lipids and proteins. Antioxidants are enzymes or other organic substances, which prevent or reduce damage caused by free radicals. N-acetyl-L-cysteine (NAC), a thiol compound, shows its effects as an antioxidant by scavenging free radicals directly or by being the precurser of glutathione, which is an important protective agent against free radicals in vivo.The aim of this study was to investigate the potential radioprotective properties of NAC against irradiation-induced oxidative damages in the liver tissues of guinea pigs after total body irradiation with a single dose of 485 cGy. After 24 h following radiation exposure, an increase was observed in the levels both of liver thiobarbuturic acid reactive substance (TBARS), which is an indicator of lipid peroxidation, and hydroxyproline (HYP), which is a major component of collagen and an indicator of tissue fibrosis. Concurrently, administration of NAC (200 mg/kg IP) in the irradiated group for 5 consecutive days before radiation exposure apparently diminished activities of lipid peroxidation and ameliorated accumulation of hydroxyproline in liver.In conclusion, the data obtained from this study indicate that application of NAC increased the functions of endogeneous antioxidant defense mechanisms in guinea pigs, and hence protected the organisms from radiation-induced liver damages.