探索Sertoli细胞对去除精原细胞的动态反应

Exploration of the dynamic responses of Sertoli cells to depletion of spermatogonial stem cells in mouse testis

目的探索Sertoli细胞对去除小鼠精原细胞后睾丸的动态反应。方法采用15、30和44 mg/kg的白消安腹腔注射法建立不同程度去除精原细胞的动物模型,处理后5 d和28 d时对睾丸进行组织学检测,评价精子发生状态,并运用实时定量荧光PCR技术检测这两个时期睾丸GDNF、PLZF、Nanog和GFRα1基因mRNA的表达量。结果在白消安处理后第5天,GDNF出现显著升高,且呈剂量依赖趋势,而PLZF与GFRɑ1并无显著变化,睾丸组织学观察亦无明显变化。在白消安处理后28 d时,GDNF、PLZF、Nanog、GFRɑ1基因mRNA相对表达量均出现大幅度的升高,睾丸组织学切片观察显示随着给药剂量的增加,精子发生受到的损伤愈加严重。结论 Sertoli细胞早在白消安处理后第5天就对精原细胞的变化发生了反应,Sertoli细胞分泌GDNF的能力发生代偿性增加,进而刺激精原干细胞自我更新速度加快,体现在Nanog和PLZF水平提高,从而实现精子发生的重建。

Objective To explore the dynamic responses of Sertoli cells to depletion of spermatogonial stem cells by busulfan.Methods After intraperitoneal injection of 15, 30 or 44 mg/kg busulfan to mice, the spermatogenesis and the expression of GDNF, PLZF, Nanog and GFRɑ1 mRNA were assessed by real-time quantitative PCR at 5 and 28 days after the busulfan treatment.Results Glial cell line-derived neutrophic factor （ GDNF ） was significantly increased and showed a dose-dependent trend at 5 days after busulfan treatment, but no significant difference was seen in the expression of promyelocytic leukemia zinc finger（PLZF） and GDNF family receptorα-1（GFRα1）.The testicular histology also appeared no significant difference at 5 days after busulfan treatment.At 28 days after busulfan treatment, the relative expression lev-els of GDNF, PLZF, Nanog and GFRɑ1 mRNA were drastically increased.Morphological observation showed that spermat-ogenesis damages became even more severe as the busulfan dose increased.Conclusions Sertoli cell response to the de-pletion of spermatogonia occurs as early as the fifth day after busulfan treatment.Production of GDNF in Sertoli cells shows a compensatory increase, which may stimulate spermatogonial stem cells to accelerate their self-renewal, reflected by the enhancing expression of Nanog and PLZF, and ultimately promote the restoration of spermatogenesis.