低氧对大鼠睾丸生殖细胞凋亡的影响

Hypoxia Promotes Apoptosis of Germ Cells in Rat Testes

目的:研究低氧对大鼠睾丸生殖细胞凋亡和Bax、Bcl-2表达的影响。方法:雄性成年Wistar大鼠随机分为4组:常氧对照组、低氧5 d组、低氧15 d组和低氧30 d组(各组n=6)。常氧对照组在平原喂养;低氧5 d组、15 d组和30 d组分别在低压舱内模拟5 000 m高原喂养5、15、30 d。采用流式细胞术和TUNEL法检测低氧对睾丸生殖细胞凋亡的影响。运用Western印迹技术检测低氧对大鼠睾丸内凋亡相关蛋白Bax、Bcl-2表达的影响。结果:低氧5 d组、15 d组和30 d组睾丸内发生生殖细胞凋亡的生精小管数量[每100个生精小管中,含有凋亡生殖细胞的生精小管数分别为(20.50±5.07)、(21.25±7.85)、(14.00±2.45)个]均非常显著地高于常氧对照组[(6.00±2.16)个,P<0.01]。凋亡的生殖细胞以精原和精母细胞为主。低氧15 d组睾丸组织亚单倍体细胞百分率[(2.18±0.82)%]显著高于常氧对照组[(1.30±0.33)%,P<0.05],低氧30 d组[(3.08±0.93)%]极显著高于常氧对照组(P<0.01)。低氧30 d组睾丸组织Bax表达显著高于常氧对照组(P<0.05),其灰度值分别为17.34±4.54和10.50±2.82。低氧30 d组睾丸组织Bax/Bcl-2比值显著高于常氧对照组(P<0.01),比值分别为0.40±0.10和0.27±0.04。结论:低氧诱导大鼠睾丸生殖细胞凋亡增多,慢性低氧引起的睾丸生殖细胞凋亡增多与Bax表达增加有关。

Objective ： To explore the effects of hypobaric hypoxia on the apoptosis of germ cells in male rats. Methods ： Adult male Wistar rats were randomly divided into four groups： a control group raised at sea level; a 5 d, a 15 d and a 30 d hypoxic group raised in a hypobaric chamber simulating 5 000 m altitude for 5 days, 15 days and 30 days respectively. Flow cytometry and TUNEL were used to evaluate the apoptosis of germ cells in the testis. Bax and Bcl-2 in the testis were measured by Western blot. Results ： Seminiferous tubules with apoptotic germ cells were significantly more in the hypoxic groups than in the control （ P 〈 0.01 ）. Most apoptotic germ cells were spermatogonia and spermatocytes. Compared with the control group, apoptotic germ cells detected by PI flow cytometry were significantly increased in the hypoxic 15 d and 30 d groups（ P 〈 0.05 ） ; Bax was significantly higher（ P 〈 0.05 ）, and so was the ratio of Bax to Bcl-2 in the hypoxic 30 d group （ P 〈 0.01 ）. Conclusion ： Hypoxia promotes apoptosis of testicular germ cells in male rats. Chronic hypoxia increases Bax expression in the rat testis.