大鼠睾丸发育过程中促甲状腺激素释放激素受体mRNA的表达

EXPRESSION OF THYROTROPIN-RELEASING HORMONE RECEPTOR mRNA IN THE RAT TESTIS DEVELOPMENT

为研究促甲状腺激素释放激素受体(TRH-R)在大鼠睾丸组织中的表达规律和在生殖发育调节中的作用,依据大鼠垂体中的TRH-R cDNA设计引物,采用RT-PCR法从大鼠睾丸组织中获得了TRH-R的cDNA克隆,测序表明其核苷酸序列与大鼠垂体中的TRH-R cDNA序列完全一致。应用非放射性原位杂交(NR-ISH)技术观察TRH-R mRNA在大鼠睾丸中的定位,结果显示杂交信号集中在间质细胞中,生精细胞无杂交信号。利用实时动态定量RT-PCR法观察了TRH-R在不同发育阶段大鼠睾丸中的表达变化,发现在睾丸间质细胞发育的初期阶段(第8天),没有TRH-R的表达,但从第15天起能观察到TRH-R的表达,并且表达量在20天、35天、60天、90天逐渐增加。这些结果表明,大鼠睾丸组织间质细胞能特异性表达TRH-R,并且表达量与发育过程相关。

In order to investigate the regulation of thyrotrophin-releasing hormone receptor (TRH-R) expression in rat testis, and to study their function in spermatogenesis, oligonucleotide primers were designed from the sequences of rat pituitary TRH-R cDNA for reverse transcription-polymerase chain reaction (RT-PCR). Specific fragments of TRH-R cDNA were cloned. DNA sequence analysis indicated that cDNA sequence of TRH-R from rat testis was consistent with those of pituitary TRH-R cDNA. The non-radioactive in situ hybridization ( NR-ISH) technique was applied to localize cells encoding TRH-R mRNA in the rat testis. Hybridization signals were detected exclusively in the leydig cells, but not in the spermatogenetic cells of the rat testis. TRH-R mRNA in the testis was quantitated in RNA samples prepared from rats at different developmental stages by real time quantitative RT-PCR. The quantitative analyses demonstrated that no TRH mRNA could be detected at the earliest stage (day 8). TRH mRNA signals were detected on day 15 and increased progressively on day 20, 35, 60 and 90. These results suggested that rat testis could specifically express TRH-R, and the transcription of TRH-R gene in the rat testis was development-dependent.