Effects of N 1-methylnicotinamide on oxidative and glycooxidative stress markers in rats with streptozotocin-induced diabetes mellitus

Abstract

Objectives: This study was focused on the monitoring how the anti-inflammatory substance, N 1- methylnicotinamide (MNA), could influence oxidation and glycooxidation stress markers in rats under conditions of streptozotocin (STZ)-induced diabetes mellitus. Methods: Diabetes mellitus was induced in 60 male Wistar rats by intraperitoneal injection of STZ and after 7 days diabetic animals were allocated to five groups according to the dose of MNA administered for 7 weeks. The degree of DNA damage in lymphocytes, as well as advanced glycation endproducts (AGEs), protein carbonyls, lipid peroxides, and total antioxidant capacity (TEAC) in plasma were measured. Results: Glycation damage to proteins (represented by AGEs level) was significantly increased in all diabetic groups compared to untreated non-diabetic animals. MNA did not affect TEAC of plasma in any group of diabetic rats. Supplementation of diabetic rats with MNA at the dose of 200 mg/kg resulted in decreased protein carbonyls (from 0.0818 ± 0.0091 to 0.0558 ± 0.0044 nmol/mg proteins; P < 0.05, n = 15) and DNA oxidation, reflected by the levels of 8-oxoG (0.6302 ± 0.085 vs. 0.9213 ± 0.108 8-oxoG/10 6 G; P < 0.05, n = 15), compared to untreated diabetic animals. Discussion: Our results demonstrated that MNA at suitable concentrations could influence oxidative modifications of proteins and DNA. © W.S. Maney & Son Ltd 2012.