外源性雄激素对大鼠胸腺细胞凋亡及Bcl-2、Bax表达的影响

Effects of exogenous testosterone on thymus cell apoptosis and expression of Bcl-2 and Bax in rats

目的探讨丙酸睾酮诱导大鼠胸腺细胞凋亡和Bcl-2、Bax表达的影响及其机制。方法雄性大鼠切除双侧睾丸,手术后第7天给予丙酸睾酮皮下注射,24 h后取其胸腺,计算胸腺指数;Hochest 33342染色荧光观察胸腺细胞凋亡情况;原位杂交技术检测胸腺凋亡基因蛋白Bcl-2、Bax mRNA的表达变化。结果双侧睾丸切除+雄激素组大鼠胸腺指数明显降低,较双侧睾丸切除组差异显著(P<0.05);假手术组、双侧睾丸切除组大鼠胸腺组织中以正常胸腺细胞为主,偶见凋亡细胞或凋亡小体,双侧睾丸切除+雄激素组可见凋亡细胞染色质碎裂,细胞核形态不规则,固缩凝聚,凋亡细胞和凋亡小体明显增多;和睾丸切除组比较,双侧睾丸切除+雄激素组大鼠胸腺组织中Bcl-2表达明显降低,而Bax表达呈现相反趋势(P<0.05)。结论雄激素可以降低大鼠胸腺指数,抑制胸腺组织中Bcl-2的表达,促进Bax的表达,从而促进雌性大鼠胸腺退化,诱导大鼠胸腺细胞凋亡。

Objective To investigate the effect of androgen on cell apoptotic changes and the expression of Bcl-2 and Bax in rats thymuses.Methods Male rats castrated were injected with testosterone propionate.The thymuses are obtained after the injection 7 days.The thymic indeices were measured.Apoptosis of thymus cells were detected after Hochest 33342 stained.The expression of Bcl-2 and Bax in thymus were detected by in site hybridization.The test were took in statistical treatment.Results The thymus quality indexes in androgen group is lower than those of castrated group（P0.05）.Apoptotic cells and apoptotic bodies were found more in thymuses of the group treated with testosterone propionate than those of castrated group.Expression of Bcl-2 in castrated group was higher than that in androgen group（P0.05）.Reversely,the expression of Bax was lower in castrated group than in androgen group.Conclusion Testosterone propionate probably induces the apoptosis of the thymocytes in male rats and restrains the Bcl-2 expression and promotes the Bax expression in thymus tissue.