不同发育时期蒙古马睾丸组织中GH和IGF-Ⅰ及其受体的表达

Expression profiles of GH,IGF-Ⅰ and their corresponding receptors in testicular tissue of Mongolian horses at different developmental stages

为进一步揭示蒙古马发育与生殖调控的分子机制提供试验数据和理论依据,研究不同发育年龄蒙古马睾丸组织中生长激素(Growth hormone,GH)、生长激素受体(Growth hormone receptor,GHR)、胰岛素样生长因子Ⅰ(Insulin-like growth factorsⅠ,IGF-Ⅰ)和胰岛素样生长因子Ⅰ受体(Insulin-like growth factorⅠreceptor,IGF-ⅠR)表达的发育性变化模式,以性成熟前期(5匹)、性成熟期(5匹)、成年期(5匹)的蒙古公马为研究对象,采集其睾丸组织,利用实时荧光定量PCR法(RT-qPCR)对不同发育年龄蒙古马睾丸组织中的GH、GHR、IGF-Ⅰ和IGF-ⅠR基因的表达差异进行分析,采用免疫组织化学方法对性成熟前期和性成熟期蒙古马睾丸组织中的GH和IGF-Ⅰ蛋白质进行定位。RT-qPCR试验结果表明蒙古马睾丸组织中上述4个基因的表达量从性成熟前期到性成熟期显著增加,成年期下降。免疫组织化学结果表明GH和IGF-Ⅰ免疫标记定位于精母细胞、精原细胞、精子细胞和睾丸间质细胞,其在相关细胞中的信号从性成熟前期到性成熟期逐渐增强。研究发现睾丸组织中GH、GHR、IGF-Ⅰ和IGF-ⅠR的mRNA协同表达对蒙古马睾丸发育和性成熟有重要调节作用,GH和IGF-Ⅰ蛋白可能通过自分泌/旁分泌的方式调节蒙古马的精子形成和睾丸间质细胞的功能。

To provide basis for further unraveling the mechanisms of development and reproduction regulation of Mongolian horse, the developmental pattern of growth hormone (GH), growth hormone receptor (GHR), insulin-like growth factors Ⅰ (IGF-Ⅰ) and insulin-like growth factor Ⅰ receptor (IGF-ⅠR) expression in testicular tissue of Mongolian horse were assessed at both gene and protein level. Fifteen Mongolian horses at the early maturation (n=5), sexual maturity period (n=5) and adulthood (n=5) were selected as experimental animals in this study. The expression profile of GH, GHR, IGF-Ⅰ and IGF-ⅠR genes in testicular tissue of Mongolian horses at the early maturation, sexual maturity period and adulthood were evaluated by SYBR Green Ⅱ-based RT-qPCR assay. The existence and location of GH and IGF-Ⅰ proteins in testicular tissue of Mongolian horses at the early maturation and sexual maturity period were identified by immunohistochemical method. The RT-qPCR assay demonstrated that the mRNA expression level of the four genes was all gradually increased from the early maturation to sexual maturity period and was subsequently decreased at adulthood. Immunohistochemical analysis showed that the germ cells and Leydig cells were found to be positive for GH and IGF-Ⅰ proteins expression;the expression of GH and IGF-Ⅰ proteins was gradually enhanced in both of the cells from the early maturation to sexual maturity period. In conclusion, the co-expression of GH, GHR, IGF-I and IGF-ⅠR mRNA displayed an important regulating effect on the development and sexual maturation of Mongolian horses, and the GH and IGF-Ⅰ proteins might regulate the spermatogenesis and Leydig cells function in an autocrine/paracrine manner.