Perrard Marie-Hélène, Durand Philippe
Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Université Lyon I, CNRS, INRA, Ecole Normale Supérieure de Lyon, Lyon, F 69364, France.
Microsc Res Tech. 2009 Aug;72(8):596-602. doi: 10.1002/jemt.20706.
We have previously shown that in cocultures of late pachytene/diplotene spermatocytes (PS/DS) with Sertoli cells, beta-nerve growth factor (beta-NGF) or transforming growth factor (TGFbeta1) regulates the second meiotic division by blocking secondary spermatocytes in metaphase II, and thereby lowers round spermatid formation. In this study, we raised the question if beta-NGF and TGFbeta1 have additional or redundant effects on this step. Hence, we addressed the effect of beta-NGF in combination with TGFbeta1, as compared to those of beta-NGF or TGFbeta1 separately, on the completion of meiosis by rat late PS/DS. Identification and counting of meiotic cells were performed by cytological methods. Under our culture conditions, some late PS/DS differentiated into round spermatids. When beta-NGF in combination with TGFbeta1 was added to the culture medium, the numbers of PS/DS and of secondary spermatocytes were not modified by the treatment. By contrast, the number of round spermatids was about 2-fold lower in treated cultures than in basal cultures, and an increase in metaphase II, but not metaphase I, over basal values was observed. Similar results were found when either beta-NGF or TGFbeta1 was added to the culture medium. These results indicate a redundancy between beta-NGF and TGFbeta1 on the negative regulation of the second meiotic division of rat spermatocytes. This suggests that beta-NGF and TGFbeta1 share some common pathway of regulation of this step. In addition, these results reinforce the view that the adjustment of the number of round spermatids supported by Sertoli cells is a key event of the spermatogenic process.
我们之前已经表明，在晚期粗线期/双线期精母细胞（PS/DS）与支持细胞的共培养中，β-神经生长因子（β-NGF）或转化生长因子（TGFβ1）通过将次级精母细胞阻滞在中期II来调节第二次减数分裂，从而降低圆形精子细胞的形成。在本研究中，我们提出了β-NGF和TGFβ1在此步骤中是否具有额外或冗余作用的问题。因此，我们探讨了与单独使用β-NGF或TGFβ1相比，β-NGF与TGFβ1联合使用对大鼠晚期PS/DS减数分裂完成的影响。通过细胞学方法对减数分裂细胞进行鉴定和计数。在我们的培养条件下，一些晚期PS/DS分化为圆形精子细胞。当将β-NGF与TGFβ1联合添加到培养基中时，处理并未改变PS/DS和次级精母细胞的数量。相比之下，处理后的培养物中圆形精子细胞的数量比基础培养物中低约2倍，并且观察到中期II而非中期I的数量相对于基础值有所增加。当单独向培养基中添加β-NGF或TGFβ1时也发现了类似的结果。这些结果表明β-NGF和TGFβ1在大鼠精母细胞第二次减数分裂的负调控方面存在冗余。这表明β-NGF和TGFβ1在该步骤的调节中共享一些共同途径。此外，这些结果强化了这样一种观点，即支持细胞所支持的圆形精子细胞数量的调节是生精过程中的一个关键事件。
