The Effects of L-Carnitine on Protein Oxidation of Streptozotocin-Induced Diabetic Rats

It has been reported that there is a significant protein oxidation resulted from oxidative damage in patients with diabetes mellitus. The aim of this study is to investigate the effects of L-carnitine which has antioxidant activity on protein oxidation seen in diabetes. In the study, twenty adult male rats of Wistar strain were randomly divided into three groups as follows: control (n=5), diabetes (n=8) and L-carnitine+diabetes groups (n=7). Diabetes and L-carnitine+diabetes groups were intraperitonally injected with a single dose of 50 mg/kg streptozotocin prepared in the citrate buffer (pH 4.5). Control group was injected with only citrate buffer. 72 hours after the streptozotocin injection, L-carnitine was given intraperitonally (500 mg/kg/day) to L-carnitine+diabetes groups for 15 days. Physiological saline was given intraperitonally to other groups for 15 days. The levels of blood sugar (at 72 hours and 2(nd) week) and kidney tissue advanced oxidation protein products of diabetes and L-carnitine+diabetes groups were higher than those in control group (p<0.001, p<0.05 and p<0.01; respectively). Kidney protein carbonyl level of diabetes group was higher when compared with the control group and L-carnitine+diabetes group (p<0.01 for both). There was a significant positive correlation between kidney tissue total and protein thiol levels in all groups. As a result; we can report that L-carnitine partially prevents protein oxidation seen in diabetes mellitus.