Streptozotocin-induced diabetes increases the interaction of Bad/BCl-XL and decreases the binding of pBad/14-3-3 in rat testis

Sexual dysfunction is frequently associated with diabetes in males. The present study was designed to evaluate whether streptozotocin-induced diabetes increases apoptotic cell death in rat testis through the regulation of Bcl-2 family proteins. Diabetes was induced by a single intravenous injection of streptozotocin (40 mg/kg body weight) and testis samples were collected after 3 months. The number of positive cells for TUNEL histochemistry was significantly increased in the testicular germ cells of the diabetic group, compared to those of control. The levels of Bcl-2 and Bcl-X-L, anti-apoptotic proteins, were decreased in the diabetic group. In contrast, the levels of Bax and Bad, pro-apoptotic factors, were increased in the diabetic group, compared with the control group. Moreover, the diabetic condition increased the interaction of Bad and Bcl-X-L, and decreased the binding of pBad and 14-3-3. 14-3-3 acts as an anti-apoptotic factor through interaction with Bad. Our findings suggest that streptozotocin-induced diabetes increases apoptotic cell death in testis tissue through the up-and down-regulation of Bcl-2 family proteins and the interaction of Bad and Bcl-X-L. (C)2007 Elsevier Inc. All rights reserved.