不同性激素对大鼠睾丸下降的影响及其与胰岛素样因子3mRNA表达的关系

Effect of different sex hormones on testicular descent and their relation to expression of INSL3 mRNA in rats

目的观察苯甲酸雌二醇(E2)、人绒毛膜促性腺激素(hCG)、促黄体激素释放激素(LHRH)对大鼠睾丸下降的影响及其与胰岛素样因子3(INSL3)表达的关系。方法将刚出生的40只SD雄性大鼠分成4组。每组10只,在生后29 d内分别给每组每天注射生理盐水、E_2、hCG+E_2、LHRH+E_2。第30天从睾丸组织抽提RNA,通过RT-PCR分析INSL3的表达。结果(1)第30天生理盐水组睾丸下降率100%(20/20),E_2组为0%(0/20),hCG+E_2组为85%(17/20),LHRH+E_2组为70%(14/20)。后两组之间差别无统计学意义(P=0．45)。(2)各组睾丸重量差异有统计学意义(F=56．67,P＜0．01),最轻的是E_2组。(3)E_2损害了睾丸生精细胞,然而hCG、LHRH能改善上述情况。(4)E_2组没有INSL3 mRNA的表达,而其他组均有正常表达。结论E_2能抑制大鼠睾丸的下降,而hCG、LHRH能促使大鼠睾丸的下降,其机制可能与INSL3 mRNA的表达有关。

Objective To observe the effects of estradiol benzoate （E2 ）, human chorionic gonadotropin （hCG） and luteinizing hormone-releasing hormone （LHRH） on testicular descent and their relation to the expression of insulin-like factor-3 （ INSL3 ） mRNA in rats. Methods At birth, 40 SD male rats were assigned to 4 groups, and each group consisted of 10 rats. Each group received injection of one of the following drugs： normal saline（ NS）, E2, hCG ＋ E2, and LHRH ＋ E2 for 29 days after birth. Total RNA was extracted from the testis on day 30 after birth. INSL3 was synthesized and further amplified by RT-PCR. Results （ 1 ） Testicular descent rate on day 30 after birth was 100% （20/20） in the group of NS, 0% （0/20） in the group of E2, 85% （17/20） of hCG ＋ E2, and 70% （14/20） of LHRH ＋ E2. There was no significant difference between the last two groups （P = 0.45 ）. （2） Weight of testis differed significantly among the groups （ F = 56.67, P 〈 0.01 ）, being lightest in the group of E2. （3） E2 could damage the germ cells of testis, however hCG and LHRH amdiorated this situation. （4） The expression of INSL3 mRNA was absent in the group of E2, while the other groups showed normal expression. Conclusion E2 inhibits testicular descent in rats, while hCG and LHRH promote the progress. The mechanism seems to be related to the expression of INSL3 mRNA.