睾酮类避孕药对大鼠生精细胞凋亡的影响

目的:研究睾酮类避孕药丙酸睾丸酮对大鼠生精细胞凋亡的影响及其机制.方法:30只35日龄雄性SD大鼠,随机分为实验组和对照组,每组15只.实验组每天肌内注射内酸睾丸酮40 mg/kg,对照组注射生理盐水.于大鼠出生第50天取血,并处死大鼠切取双侧睾丸.应用原位末端标记检测、流式细胞测定(FCM)、电镜及放射免疫等技术,对大鼠睾丸生精细胞的凋亡进行定性、定位和定量研究.结果:与对照组相比,实验组大鼠睾丸生精细胞凋亡数量增多,主要为初级精母细胞;实验组、对照组大鼠生殖细胞凋亡率分别为(11.3±0.9)%和(3.6±2.3)%,1C峰细胞的百分比分别为(21.8±7.1)%和(33.8±7.5)%,2C峰细胞的百分比分别为(52.6±8.2)%和(37.1±12.5)%,差别均有统计学意义(P＜0.01).实验组和对照组大鼠血清中睾酮水平分别为(3486.8±333.3)ns/L和(846.9±167.5)ng/L,卵泡刺激素水平分别为(2.5±0.8)IU/L和(5.2±1.7)IU/L.差别均有统计学意义(P＜0.01).结论:外源性丙酸睾丸酮可能通过反馈性抑制垂体性腺轴而诱导生精细胞凋亡,发挥其避孕的作用.

Effect of Testosterone Propionate on Apoptosis of Rat Germ Cells

Objective: To investigate the effects of the exogenous testosterone propionate on apoptosis of rat germ cells and the mechanisms thereof. Methods: Thirty 35-day-old male SD rats were randomly divided into experimental group and the control group. The rats in experimental group were injected (i.m.) testosterone propionate and the control group with an equal volume of saline. By using terminal deoxynueleotidy transferase nediated dUTP nick-end labeling (TUNEL), flow cytometry (FCM), radioimmunoassay (RIA) and electron microscopy, the quantity and quality of apoptosis of germ cells were evaluated. Results:(1) Compared with the control, the apoptotic number of rat germ cells was increased in the experimental group, especially the primary spermatocyte. The apoptotie rate was 11.3% detected by FCM in experimental group,while 3.6% in the control group (P ＜ 0.01). (2) The percentages of 1C were 21.8% in experimental group and 33.8% in control group (P ＜ 0.01).The percentages of 2C were 52.6% in experimental group and 37.1% in control group (P ＜ 0.01). (3) The serum levels of testosterone were (3 486.8±333.3) ng/L in experimental group and (846.9±167.5) ng/L in control group (P ＜ 0.01). The serum levels of follicle-stimulating hormone (FSH) were (2.5±0.8) IU/L in experimental group and (5.2±1.7) IU/L in control group (P ＜0.01). Conclusion: The exogenous testosterone propionate might induce apoptosis of germ cells by retroinhibition of the hypothalamie-pituitary-gonadal axis, thus having contraceptive effects.