Myocardial effects of ethanol consumption in the rat with streptozotocin-induced diabetes

Background: Rats with streptozotocin (STZ)-induced diabetes exhibit alterations in cardiac function, ventricular remodeling, and changes in cell signaling, which includes protein kinase C (PKC) isoforms. Moderate consumption of ethanol has a beneficial effect on cardiovascular outcomes in the general population, an effect that has recently been found to extend to patients with diabetes mellitus. We studied the effect of low-dose ethanol consumption on cardiac function, geometry. and PKC isoforms in the rat with STZ-induced diabetes. Methods: Four groups of rats were studied over 8 to 10 weeks: control, STZ-induced diabetes, 12% (v/v) ethanol consumption, and STZ-induced diabetes plus 4% (v/v) ethanol consumption. Invasive hemodynamic measurements were performed; myocardial tissue was obtained for analysis for total PKC and cytosolic and membrane protein content of PKC-alpha,PKC-delta, and PKC-epsilon, and two-dimensional and M-mode echocardiograms were obtained. Results: Compared with rats with diabetes alone, consumption of 4% ethanol prevented the decrease in left ventricular dP/dt seen with diabetes alone, as well as the increase in left ventricular internal dimension. Up-regulation of PKC-alpha, -delta, and -epsilon occurring in the diabetic animals was also prevented by ethanol consumption, whereas ethanol alone had no effect on PKC isoform pattern. Conclusions: These data suggest that STZ-induced cardiac remodeling and dysfunction are associated with increases in PKC activity, particularly PKC-alpha, -delta,and -epsilon and that consumption of ethanol can prevent these changes.