Role of soy protein concentrate on oxidative stress and DNA fragmentation in streptozotocin-induced diabetic rats

Abstract

Diabetes mellitus is currently a major public health concern with many pathophysiological alterations; this study aimed to evaluate the antidiabetic and protective potential of soy protein concentrate (SPC) against diabetes mellitus induced by streptozotocin (STZ) in adult male Spargue Dawely rats. The hyperglycemic groups were made with a single (ip) dose of STZ (55mg/kg b.w.). Five groups of rats were used; normal control group, SPC (200 mg/kg/day) treated group, hyperglycemic untreated group, hyperglycemic-diamicrone^® 30MR (10 mg/kg/day) treated group and hyperglycemic-SPC (200 mg/kg/day) treated group. The experiment lasted for six weeks. The results revealed significant increases in blood glucose, hepatic and renal MDA and NO contents concomitant with significant depletion of GSH content and decreases in insulin level, SOD and CAT activities in the diabetic group; moreover, significant increases in serum ASAT, ALAT, GGT, urea, creainine, total cholesterol, LDL- cholesterol and triglycerides matched with a significant reduction in HDL- cholesterol and body weight values were noticed compared to control values. Interestingly, significant improvements in all biochemical, DNA fragmentation and histological determinations were observed in the diabetic-SPC treated group compared to diabetic group, especially DNA fragmentation percent. Also, diamicrone^® significantly ameliorated the severity of STZ induced changes in the above mentioned parameters with the exception of DNA fragmentation which was severely elevated than diabetic group; reflecting the necessary to find more safer alternative treatments.  In conclusion: the relative hypoglycemic and highly protective effects of SPC against STZ-induced diabetes mellitus may be attributed to its antioxidant and free radical scavenging mechanisms that due to its higher contents of thiol-rich amino acids and antioxidant ones