Changes in prooxidant-antioxidant balance in tissues of rats following long-term hyperglycemic status.

Introduction: Reactive oxygen species play an important role in the pathogenesis of organ damage in diabetes mellitus. Streptozotosin (STZ) is a commonly employed compound to produce diabetes mellitus and these animals exhibit most of diabetic complications.

Methods: In our study, diabetes was induced by a single intraperitoneal injection of STZ at a dose of 50 mg/kg in rats and they were killed 12 weeks after STZ. Endogenous lipid peroxide levels, enzymatic and non-enzymatic antioxidants were measured in liver, heart, kidney, brain, and testis tissues to investigate the effect of long-term hyperglycemic state. The susceptibility of diabetic tissues to oxidative stress was also examined in in vitro oxidizing system containing ascorbic acid and iron.

Results: We found that prooxidant and antioxidant balance has changed in favor of prooxidation in the tissues of diabetic rats. The susceptibility of liver to oxidative stress increased; however, this susceptibility did not change in heart, kidney, brain, and testis of diabetic rats.

Conclusion: Our results indicate that long-term hyperglycemic state disturbs hepatic prooxidant-antioxidant balance at an earlier period and more pronouncedly than other tissues.