Taurine attenuates oxidative stress and alleviates cardiac failure in type I diabetic rats

AIM: To investigate cardioprotective effect of taurine in diabetic rats. METHODS: Male Sprague-Dawley rats were assigned randomly into four groups of 15 rats: control group, control + taurine group, streptozotocin (STZ) group, and STZ + taurine group. Rats in STZ and STZ+ taurine groups were treated by a single injection of STZ (70 mg kg(-1), intraperitoneally) dissolved in 0.01 M citrate buffer (pH 4.5) for induction of diabetes, and rats in control and control + taurine groups were treated with the same volume citrate buffer. Taurine was orally administered to rats in control + taurine and STZ + taurine groups daily for 8 weeks. Rats were examined for diabetic cardiomyopathy by left ventricular (LV) hemodynamic analysis. Myocardial oxidative stress was assessed by measuring the activity of superoxide dismutase (SOD) and the level of malondialdehyde (MDA). Myocardial protein kinase B (Akt/PKB) phosphorylation and heme oxygenase-1 (HO-1) protein levels were measured by Western blot in all rats at the end of the study. RESULTS: In untreated diabetic rats, LV systolic pressure, rate of pressure rise, and rate of pressure fall were decreased, while LV end-diastolic pressure was increased, indicating reduced LV contractility and slowing of LV relaxation. The levels of Akt/PKB phosphorylation and SOD activity were decreased and HO-1 protein expression and MDA content increased. Taurine treatment significantly improved LV systolic and diastolic function, and there were persistent increases in activities of Akt/PKB and SOD, and the level of HO-1 protein. CONCLUSION: Taurine treatment ameliorates myocardial function and heart oxidant status, while increasing myocardial Akt/PKB phosphorylation, and HO-1 levels have beneficial effects on diabetic cardiomyopathy.