The influence of NO synthase inhibitor and free oxygen radicals scavenger--methylene blue--on streptozotocin-induced diabetes in rats.
The excessive production of nitric oxide (NO) and the subsequent increase of local oxidative stress is suggested as one of the pathophysiological mechanisms of streptozotocin-induced diabetes. It was reported that the administration of NO synthase inhibitors partially attenuated the development of streptozotocin-induced diabetes and reduced hyperglycaemia. Here we have studied the influence of methylene blue, which combines the properties of NO synthase inhibitor with antioxidant effects. The experiments were performed on male rats divided into four groups: control, diabetic (single dose of 70 mg of streptozotocin/kg i.p.), methylene blue (50 mg/kg in the food) and diabetic simultaneously fed with methylene blue. After 45 days the experiments were discontinued by decapitation. Serum glycaemia, glycated haemoglobin and oxidative stress parameters (plasma malondialdehyde concentration and erythrocyte superoxide dismutase activity) were significantly higher in the diabetic group. Simultaneous methylene blue administration partially reduced glycaemia and glycated haemoglobin, but did not decrease oxidative stress. We conclude that NO synthase inhibitor methylene blue partially attenuates the development of streptozotocin-induced diabetes in male rats, but does not reduce the development of oxidative stress in the diabetic group.
Third Medical Department, First Faculty of Medicine, Charles University, Prague, Czech Republic.
M
M
Haluzík
J
J
Nedvídková
J
J
Skrha
D000818:Animals; D000975:Antioxidants / Q000627:therapeutic use*; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology / Q000517:prevention & control*; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D016166:Free Radical Scavengers / Q000627:therapeutic use*; D006442:Glycated Hemoglobin / Q000378:metabolism; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008751:Methylene Blue / Q000627:therapeutic use*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D018384:Oxidative Stress; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000097:blood; D015431:Weight Loss
D000975:Antioxidants; D001786:Blood Glucose; D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; D006442:Glycated Hemoglobin; D008315:Malondialdehyde; D008751:Methylene Blue; D019001:Nitric Oxide Synthase; D013482:Superoxide Dismutase