皮质酮诱导的大鼠Leydig细胞凋亡中caspase-3活化途径的研究

目的我们新近的研究表明，超生理剂量的皮质酮（大鼠体内的糖皮质激素）可通过激活caspase-3诱导大鼠Leydig细胞凋亡。本研究拟评价在皮质酮诱导的大鼠Leydig细胞凋亡过程中，caspase-3的激活是否有其上游的caspase-8平和 caspase-9的参与。方法采用荧光分光光度法榆测经皮质酮处理的大鼠Leydig细胞中caspase-8活性，以DNA梯状电泳条带作为评价细胞凋亡的指标，观察caspase-8抑制剂是否能够抑制细胞凋亡，采用RTPCR枪测皮质酮诱导的大鼠Leydig细胞中caspase-9的mRNA水平。结果在皮质酮诱导的大鼠Leydig细胞中出现caspase-8活性增高，以12h最为址著，升高的caspase-8的活性可被caspase-8抑制剂抑制，并导致Leydig细胞的凋亡过程被阻断。Leydig细胞中caspase-9的mRNA水平在皮质酮作用下上升，同样以12h最为显著。结论皮质酮诱导的大鼠Leydig细胞调亡与caspase-8和caspase-9有关。

The study on activation pathway of caspase-3 in corticosterone-induced Leydig cell apoptosis

Objective To observe whether the caspase-8 and caspase-9 are involved in the CORT-mediatedLeydig cell apoptosis. Methods The caspase-8 activity in Leydig cell subjected to CORT treatment was detected byfluorescent quantitative assay. Apoptosis was demonstrated by DNA laddering electrophoresis. The levels of caspase-9 mRNA expression in the apoptotic pathway were investigated by RT-PCR. Results Caspase-8 activity in Leydigcells increased at 6h after the start of CORT administration, peaked at 12h and declined thereafter. In the presence ofa specific caspase inhibitor, IETD-FMK, Leydig cell apoptosis was suppressed and agarose gel electrophoresis showedthat marked DNA laddering typical for apoptosis was not detectable in Leydig cells treated with a dose of 100nMCORT. The expression of caspase-9 mRNA is increased during apoptosis. Conclusion caspase-8 and caspase-9 areall implicated in the process of apoptotic Leydig cell induced by CORT.