Effects of leptin on oxidative stress in healthy and Streptozotocin-induced diabetic rats
- 154 Downloads
It is generally accepted that oxidative stress is responsible for etiology and complications of diabetes. During uncontrolled Type 1 diabetes, plasma leptin levels rapidly fall. However, it is not known whether diabetes-induced hypoleptinemia has any role in oxidative stress related to uncontrolled Type I diabetes. The present study was designed to examine the effects of leptin treatment on plasma lipid peroxidation and reduced glutathion of normal and streptozotocin(STZ)-induced diabetic rats.
Diabetes was induced by single injection of Streptozotocin (55 mg/kg bw). One week after induction of diabetes, rats began 5-day treatment protocol of leptin injections of (0.1 mg/kg bw i.p.) or same volume vehicle. At the end of the 5th day, rats were sacrificed by cardiac puncture under anesthesia and their plasma was taken for plasma leptin, malondialdehyde, and reduced glutathione measurements.
Plasma leptin levels decreased in STZ-induced diabetic rats while plasma glucose, TBARS, and GSH levels increased. Plasma leptin levels were not affected with leptin treatment in both diabetic and non-diabetic rats. The elevation in plasma TBARS associated with STZ diabetes decreased with leptin treatment. Leptin also increased plasma GSH levels in diabetic rats. In non-diabetic rats, treatment with leptin did not change plasma TBARS and GSH levels.
In conclusion, leptin treatment is able to attenuate lipid peroxidation in STZ-diabetic rats, in the onset of diabetes, by increasing the GSH levels without affecting hyperglycemia and hypoleptinemia.
KeywordsOxidative stress Diabetes mellitus Streptozotocin Leptin Plasma Malondialdehyde Reduced glutathione Rat
This study was supported by Gazi University Research Foundation. (GU-BAP 01/2002-58)
- 11.Rosen P, Nawroth PP, King G, Moller W, Tritschler HJ, Packer L (2001) The role of oxidative stress in the onset and progression of diabetes and its complications: a summary of a Congress Series sponsored by UNESCO-MCBN, the American Diabetes Association and the German Diabetes Society. Diabetes Metab Res Rev 17:189–212PubMedCrossRefGoogle Scholar
- 35.Matkovics B, Kotorman M, Varga IS, Hai DQ, Varga C (1997–1998) Oxidative stress in experimental diabetes induced by streptozotocin. Acta Physiol Hung 85:29–38Google Scholar
- 42.Woods JS, Kavanagh TJ, Corral J, Reese AW, Diaz D, Ellis ME (1999) The role of glutathione in chronic adaptation to oxidative stress: studies in a normal rat kidney epithelial (NRK52E) cell model of sustained upregulation of glutathione biosynthesis. Toxicol Appl Pharmacol 160(3):207–216PubMedCrossRefGoogle Scholar