Transient ischemia induces apoptosis in the ventral prostate of the rat

The mechanisms involved in the castration-induced involution of the ventral prostate (VP) are not fully understood. It was recently reported that cast ration decreases blood flow in the VP in rats and that this occurs before t he apoptotic involution of the organ. However, it is unknown whether a decr ease in blood flow may trigger apoptosis in the VP, and this was therefore examined in this study. The right iliac artery was clamped for 1 h in adult male rats. After 24 h of reperfusion, the VPs were frozen or fixed. III si tu end-labeling (ISEL) was used to identify apoptotic cells, and testostero ne repressed prostatic message-2 (TRPM-2) was measured. Proliferating cell nuclear antigen (PCNA) immunohistochemistry was used to identify proliferat ing cells. Clamping the right iliac artery reduced blood flow in the right VP to 0.17 of that in the contralateral lobe. This relative ischemia result ed in a threefold increase in the volume density of apoptotic epithelial ce lls on the treated side, but left cell proliferation unaffected. Testostero ne substitution did not change this pattern. This study suggests that a tra nsient period of relative ischemia may induce apoptosis in the rat ventral prostate. This may be of importance for the understanding of castration-ind uced prostatic involution.