恐惧应激对大鼠睾丸生殖细胞凋亡的影响

Effects of stress induced by fear on germ cells apoptosis in rat's testis

目的观察恐惧应激对大鼠睾丸组织中生殖细胞凋亡的影响。方法36只SD大鼠随机分为急性应激组、亚急性应激组、慢性应激组和对照组,建立大鼠恐惧应激模型,在观察不同时间后取材,RT-PCR法检测睾丸组织中caspase-3、bax和bcl-2 mRNA的表达并比较bax/bcl-2的比值,TUNEL法检测睾丸内精原细胞、初级精母细胞、次级精母细胞和精子细胞的凋亡情况。结果caspase-3mRNA的表达水平,急性应激组与其对照组比较无显著差异(3.85±0.84vs3.30±0.74,P>0.05),而亚急性应激组与其对照组比较(5.34±1.13vs3.67±0.34)、慢性应激组与其对照组比较(5.88±0.31vs4.08±0.60)均显著增高(P<0.05)。bax/bcl-2比值,急性应激组与其对照组比较无显著差异(1.61±1.01vs1.15±0.29,P>0.05),而亚急性应激组与其对照组比较(2.68±0.86vs1.60±0.42,P<0.05)、慢性应激组与其对照组比较(3.88±0.60vs2.99±0.76)均显著增高(P<0.001)。急性应激组生殖细胞凋亡指数与对照组比较无显著差异(3.75±0.50vs1.50±0.58,P>0.05),而亚急性应激组(10.50±1.29)和慢性应激组(21.50±1.73)与对照组相比较均显著增高(P<0.001)。结论长期恐惧应激可导致大鼠睾丸生精细胞发生凋亡,caspase-3、bax和bcl-2等参与了其凋亡过程。

Objective To investigate the effect of stress induced by fear on germ cells apoptosis in rat＇s testis. Methods 36 SD rats were randomly assigned to acute stress group, subacute stress group, chronic stress group and control group, respectively. The model of the stress rat induced by fear was reproduced. The levels of caspase-3 mRNA and bax/bcl-2 mRNA expression in rats testis were determined by fluorescent quantitative RT-PCR. The apoptosis of spermatogonic cell, primary spermatocyte, secondary spermatocyte and sperrnatid was identified by TUNEL. Results Caspase-3 mRNA, compared with that in control group, was expressed highly in the subacute stress group （5. 34±1. 13 vs 3. 67±0. 34, P〈0. 05） and in chronic stress group （5. 88±0. 31 vs 4. 08±0.60, P〈0. 05）. There were no significant differences in easpase 3 mRNA between acute group and the control group （3. 85±0. 84 vs 3. 30±0. 74, P〉0. 05）. The ratio of bax/bel-2 mRNA, compared with that in the control group, was increased significantly in the subacute stress group （2. 68±0. 86 vs 1.60 ±0. 42, P〈0. 05） and in the chronic stress group （3. 88±0. 60 vs 2.99±0.76, P〈0. 001）. There was no significant difference between acute group and the control group （1. 61±1.01 vs 1.15±0. 29, P〉0. 05）. Compared with that in control group （1. 50±0. 58）, the apoptotic index of germ cells was higher in the subacute stress group （10. 50±1.29, P〈0. 001） and in the chronic stress group （21. 50±1.73, P〈0. 001）, and was not significantly different in the acute stress group （3.75±0. 50, P〉0. 05）. Conclusion Stress induced by fear plays an important role in inducing germ cells apoptosis, and easpase-3, bax and bel-2 were involved in this process.