细胞内Retinoid结合蛋白mRNA水平在生精过程中的周期性变化

THE PERIODIC CHANGE OF CELLULAR RETINOID BINDING PROTEIN mRNA LEVEL IN RAT TESTIS DURING THE CYCLE OF THE SEMINIFEROUS EPITHELIUM

目的 研究大鼠睾丸细胞内视黄醇结合蛋白 - (CRBP- )及细胞内视黄酸结合蛋白 - (CRABP- ) m RNA水平与曲细精管生精上皮周期的相关关系。 方法 分别以地高辛标记的大鼠 CRBP- 及 CRABP- c DNA探针在 SD大鼠睾丸冰冻切片上进行原位杂交 ,应用激光密度扫描系统对阳性信号进行定量。 结果 CRBP- 及 CRABP- m RNA在支持细胞 (sertoli cell,SC)中表达。CRBP- m RNA ～ 期处于高水平 , ～ 期达到高峰 ,至 期骤然下降 , ～ 期为低水平 ,其中 ～ 期最低 ,仅为高峰时期的 2 8%。CRABP- m RNA ～ 期为低水平 , ～ 期水平增加 1倍以上 ,其中 ～ 期达到高峰 ,随后缓慢下降。 结论 SC可合成 CRBP- 、CRABP- ,且合成量具有与生精周期相伴的周期性变化。总的来说 ～ 期合成量较高 ,生精周期后期 CRBP- 、CRABP- 的高表达提示它们在圆形精子向长形精子转变的过程中发挥作用。CRBP- ～ 期的峰值显示它对于次级精母细胞减数分裂的完成、新一轮生精周期的开始起着非常重要的作用。总之 。

Objective\ To investigate the variation of the level of rat cellular retinol\|binding protein\|Ⅰ(CRBP\|Ⅰ) and cellular retinoic acid binding protein\|Ⅱ(CRABP\|Ⅱ) mRNA in rat testis during the spermatogenetic cycle. Methods\ In situ hybridization was performed with DIG\|labeled rat CRBP\|Ⅰ or CRABP\|Ⅱ cDNA probe on male SD rats frozen tissue sections. The laser density scanning system was used to quantitate the level of the positive signal. Results\ We found that both of CRBP\|Ⅰ and CRABP\|Ⅱ genes were expressed in the SC in the testis, and a stage\|dependent variation was observed. No signal was found in the spermatogenetic cells. The CRBP\|Ⅰ mRNA levels increased from stage Ⅶ\|Ⅷ through stage Ⅸ\|Ⅺ, reached a peak during stage ⅪⅠ\|ⅪⅤ,and declined markedly between stage Ⅰ\|Ⅵ, very slight hybridization signal was seen at stage Ⅱ\|Ⅳ. The CRABP\|Ⅱ mRNA levels were two folds lower at stage Ⅰ\|Ⅵ than that detected at stage Ⅶ\|ⅪⅤ,at stage Ⅶ\|Ⅷ it reached a peak, thereafter declined. Conclusion\ The expression of both CRBP\|Ⅰ and CRABP\|Ⅱ genes was higher at stage Ⅶ\|ⅪⅤthan at stage Ⅰ\|Ⅵ. At the later of the spermatogenetic cycle the high expression of CRBP\|Ⅰ, CRABP\|Ⅱ suggested that they might play an role in the spermiogenesis from round sperm to elongated one. The peak of CRBP\|Ⅰ mRNA levels at stage ⅪⅠ\|ⅪⅤ indicated that it might play a key role in the process that the secondary spermatocytes finished meiosis and a new spermatogenetic cycle was initiated. The cyclically secreted proteins of SC may be one important factor by which SC influences spermatogenesis.\;