The corrective effect of chromium and zinc citrates on NO-synthase activity of erythrocytes in rats with streptozotocin diabetes

Abstract

The aim of the research was to investigate the effect of chromium and zinc citrates on the NO-synthase (NOS) activity of erythrocytes in rats with streptozotocin diabetes. In three series of investigations rats were divided into four groups (I — control, II, III and IV — experimental) each one containing 7 animals. During four weeks, in the first series of investigations chromium citrate was added with water to the main diet of animals in III and IV groups in amounts of 10 and 25 μg Cr3+/kg of body weight; in the second series, zinc citrate was added in amounts of 20 and 50 mg Zn2+/kg of body weight respectively. In the third series, the animals of III group received chromium citrate in amount 25 μg Cr3+/kg of body weight and zinc citrate in amount 50 mg Zn2+/kg of body weight with water. The rats of II experimental group in all series received clean water with no citrates added. A month later, in animals of all experimental groups on the background of a 24-hour fasting an experimental diabetes mellitus was induced by a single intraperitoneal injection of streptozotocin in amounts of 45 mg/kg of body weight with the previous injection of nicotinamide. Diabetes occurred on the third day. Animals with a glucose concentration of 14 mmol/L were used for the experiment. The material for the investigation was the blood of rats, in which the concentration of glucose and the relative count of glycosylated hemoglobin were determined, in erythrocytes — NO-synthase activity: general, inducible and constitutive. As a result of the conducted research, it has been found that under streptozotocin induced experimental diabetes in erythrocytes of rats of experimental group II in both series of investigations the activity of general and inducible NOS increased, while the activity of the constitutive NOS did not change compared with the animals of the control group. The introduction of chromium and zinc citrates into the animals’ diet in the above mentioned doses led to the decrease in the activity of the general and inducible NOS compared with the animals of group II with streptozotocin diabetes, indicating a positive effect of the studied microelements on NOS activity in erythrocytes of rats. Thus, the use of chromium and zinc citrates in the diet of rats with diabetes has a normalizing effect on the state of NOS activity, what can reduce the harmful influence of hyperglycemia on the development of oxidative and nitrosative stress.