目的：在哺乳類的細胞，caspase-3被認為是執行細胞凋亡的主要蛋白酶，於是我們探討活化的caspase-3在睪丸生殖細胞的表現，藉此瞭解左側精索靜脈曲張的老鼠其睪丸生殖細胞凋亡的情形。材料與方法：以24隻Sprague-Dawley成鼠做左側部分腎靜脈的結紮當實驗組，另外16隻進行假手術當對照組，分別在術後的二、四、八及十二週取下兩組的左側睪丸進行活化的caspase-3蛋白分析和免疫組織化學染色。結果：精索靜脈曲張的老鼠（實驗組）在術後的第八週及第十二週活化的caspase-3的表現量均大於對照組，且有統計意義(p<0.05)。結論：本次的動物實驗證實活化的caspase-3在睪丸的生殖細胞表現量，尤其在第八週及第十二週後實驗組明顯大於對照組；表示生殖細胞凋亡增加，這可能也是人類精索靜脈曲張病人造成不孕的原因之ㄧ。

OBJECTIVES: In mammalian cells, caspase-3 is considered to be a major executioner protease because it is essential for apoptotic cell death. We investigated the testicular germ cell apoptosis of rats with experimentally induced left varicocele by detecting activated caspase-3 expression.MATERIALS AND METHODS: An experimental left varicocele (ELV) was created by partial ligation of the left renal vein in 24 adult male Sprague-Dawley rats as the study group. An additional 16 rats that underwent a laparotomy and renal vein handling without ligation served as the sham control group. Six rats of the study group and 4 rats of the control group were sacrificed at 2, 4, 8, and 12 weeks, respectively, following varicocele creation. The testicular tissues of the varicocele and control groups were sampled for activated caspase-3 by immunoblotting and immunohistochemistry.RESULTS: Actual numbers of rats in the varicocele group were 4, 5, 6, and 5at 2, 4, 8, and 12 weeks, respectively, after varicocele creation. The immunoblots of activated caspase-3 in both control and varicocele groups revealed a single band. The relative intensities of activated caspase-3 at 8 and 12 weeks significantly increased in the varicocele group compared to the ipsilateral testis of the control group (p＜0.05).CONCLUSIONS: This animal study demonstrated increased expression of activated caspase-3 in testicular germ cells at 8 and 12 weeks after varicocele creation. That means that the increase in testicular germ cells apoptosis in rats with ELV occurred gradually. This may be a factor in varicocele causing male infertility in humans.