Caspase-3 activation is required for corticosterone-induced rat Leydig cell apoptosis

Abstract

Objective: Study on caspase-3 expression and its activation in CORT-mediated rat Leydig cell apoptosis. Methods: Caspase-3 protein activity, content and the timing of the onset of caspase-3 cleavage in relationship to CORT administration in rats was studied by Western blot. The timing of the onset of caspase-3 activity in Leydig cell was measured by the fluorescence. Results: Low molecular weight DNA fragments that are characteristic of apoptosis were evident in Leydig cells by 12 h of exposure to 100 nmol/L CORT in vitro and it was more pronounced at 24 h. Western blot analysis revealed that procaspase-3 was low in untreated Leydig cells and increased by 6 h of CORT administration. By 12 h, however, procaspase-3 was significantly reduced and the cleaved, active caspase-3 forms appeared and increased through 24 h. In the presence of a specific caspase inhibitor, Ac-DEVD-CHO, Leydig cell apoptosis was suppressed, corroborating the hypothesis that caspase-3 is involved in CORT-mediated cell death. Conclusion: Caspase-3 was implicated in CORT-mediated rat Leydig cell apoptosis.