Rode Kristina, Weider Karola, Damm Oliver Siegfried, Wistuba Joachim, Langeheine Marion, Brehm Ralph
Institute of Anatomy, University of Veterinary Medicine Hannover, Bischofsholer Damm 15, 30173 Hannover, Germany.
Laboklin GmbH und Co.KG, Steubenstraße 4, 97688 Bad Kissingen, Germany.
Reprod Biol. 2018 Dec;18(4):456-466. doi: 10.1016/j.repbio.2018.08.001. Epub 2018 Sep 19.
For the reason that adult Sertoli cell specific connexin 43 knockout (SCCx43KO) mice show arrested spermatogenesis at spermatogonial level or Sertoli cell only tubules and significantly reduced germ cell (GC) numbers, the aims of the present study were (1) to characterize the remaining GC population and (2) to elucidate possible mechanisms of their fading. Apoptosis was analyzed in both, KO and wild type (WT) male littermates during postnatal development and in adulthood using TUNEL. Although GC numbers were significantly reduced in KO at 2 and 8 days postpartum (dpp) when compared to WT, no differences were found concerning apoptotic incidence between genotypes. From 10 dpp, the substantial GC deficiency became more obvious. However, significantly higher apoptotic GC numbers were seen in WT during this period, possibly related to the first wave of spermatogenesis, a known phenomenon in normal pubertal testes associated with increased apoptosis. Characterization of residual spermatogonia in postnatal to adult KO and WT mice was performed by immunohistochemical reaction against VASA (marker of GCs in general), Lin28 and Fox01 (markers for undifferentiated spermatogonia) and Stra8 (marker for differentiating spermatogonia and early spermatocytes). During puberty, the GC component in SCCx43KO mice consisted likely of undifferentiated spermatogonia, few differentiating spermatogonia and very few early spermatocytes, which seemed to be rapidly cleared by apoptosis. In adult KOs, spermatogenesis was arrested at the level of undifferentiated spermatogonia. Overall, our data indicate that Cx43 gap junctions in SCs influence male GC development and differentiation rather than their survival.
由于成年支持细胞特异性连接蛋白43基因敲除（SCCx43KO）小鼠的精子发生在精原细胞水平停滞，或仅形成支持细胞管，且生殖细胞（GC）数量显著减少，本研究的目的是：（1） 对剩余的GC群体进行特征分析；（2） 阐明其逐渐减少的可能机制。在出生后发育阶段及成年期，使用TUNEL法对基因敲除（KO）和野生型（WT）雄性同窝小鼠的细胞凋亡情况进行分析。虽然与野生型相比，基因敲除小鼠在出生后第2天和第8天（dpp）时GC数量显著减少，但不同基因型之间的细胞凋亡发生率并无差异。从出生后第10天起，GC大量缺乏的情况变得更加明显。然而，在此期间野生型小鼠中可见显著更多的凋亡GC，这可能与精子发生的第一波有关，这是正常青春期睾丸中与凋亡增加相关的一种已知现象。通过针对VASA（一般GC的标志物）、Lin28和Fox01（未分化精原细胞的标志物）以及Stra8（分化中的精原细胞和早期精母细胞的标志物）的免疫组化反应，对出生后至成年的基因敲除和野生型小鼠中的残余精原细胞进行了特征分析。在青春期期间，SCCx43KO小鼠中的GC成分可能由未分化的精原细胞、少数分化中的精原细胞和极少数早期精母细胞组成，这些细胞似乎会通过凋亡迅速清除。在成年基因敲除小鼠中，精子发生停滞在未分化精原细胞水平。总体而言，我们的数据表明，支持细胞中的Cx43间隙连接影响雄性GC的发育和分化，而非其存活。
