环磷酰胺对不同发育时期睾丸生精细胞毒性损伤的动物实验研究

目的探讨抗肿瘤药物所致牛精细胞损害与年龄的关系，为性腺保护剂的运用寻找理论依据。方法将环磷酰胺分别作用于处于不同发育时期的1周龄、3周龄、5周龄、9周龄雄性大鼠，应用HE染色法、TUNEL法和免疫组化法检测急性期生精细胞凋亡，bcl-2蛋白表达，细胞增殖能力变化及远期组织学损害。结果用药后24h，除1周龄组外，各实验组生精细胞显著凋亡（P〈0．01），bcl-2蛋白表达显著下降（P〈0．01），生精细胞S期所占的比例显著下降（P〈0．01）。用药后9周，除1周龄组外，各实验组曲细精管面积、直径、生精上皮细胞计数、Johnsen’s评分均显著低于相应对照组（P〈0．01），并随年龄增大损害有增加趋势。结论环磷酰胺可诱导生精细胞增殖启动阶段以后的生精细胞显著凋亡，且伴有bcl-2明显下调。并可湿著抑制精原细胞和细线前期精母细胞增殖。远期组织学改变年龄越小所受的损害越小，提示为使睾丸免受抗肿瘤药物的伤害而采用性激素使生精细胞增殖分化处于不分化状态是有效的防护方法之一。

Toxic effect of cyclophosphamide on the rat spermatogenesis in different developmental phases of testes

Objective To investigate the toxic effect of cyclophosphamide (CTX) on the rat spermatogenesis in different developmental phases of testes. Methods Same dose of CTX was administered to the different ages of male Wistar rats. The testes were harvested at different time-point after administration of CTX. The histological changes were examined by light microscopy, the average diameter and area of seminiferous tubule, cell number of spermatogenic epithelium, and Johnsen's score were recorded. Moreover, the spermatogenic cell apoptosis was visualized by TUNEL, the expression of Bcl-2 protein was demonstrated by immunohistochemistry, and spermatogenic cell cycle was detected by flow cytometry. Results After 24 hours of administration of CTX, the average diameter and area of seminiferous tubule, cell number of spermatogenic epithelium, and Johnsen's score in experimental groups except 1 week group were all lower than those in controls. Except 1 week group, the apoptosis in the other experiment groups was significantly increased (P< 0.01 ), while the expression of Bcl-2 and proportion of S period cells were significantly decreased (P< 0.01 ), compared to those in the controls. Similar results could also be found after 9 weeks of administration of CTX. Moreover, the damage in the spermatogenic cells was more significant in older rats than that in younger ones. Conclusions The apoptosis of spermaotgenic cells induced by CTX may be related to the downregulation of Bcl-2. The fact of less toxic effect of CTX in younger rats indicates that there is a possibility of protective effect of hormone on rat spermatogenesis after CTX administration.