Vogl A W, Lin Y C, Dym M, Fawcett D W
Am J Anat. 1983 Sep;168(1):83-98. doi: 10.1002/aja.1001680109.
Sertoli cells of the ground squirrel (Spermophilus lateralis), a seasonal breeder, were examined by light and electron microscopy and their structure, particularly the organization of the cytoskeleton, was related to events that occur in the seminiferous epithelium during spermatogenesis. Among the events considered and described are the apical movement of elongate spermatids, withdrawal of residual cytoplasm from germ cells, transport of smooth endoplasmic reticulum (SER) between the base and apex of the Sertoli cells, and sperm release. These events are dramatically evident in this species because the seminiferous epithelium is thin, i.e., there are few germ cells, and both the germ cells and Sertoli cells are large. Sertoli cells of the ground squirrel have a remarkably well developed cytoskeleton. Microfilaments occur throughout the cell but are most evident in ectoplasmic specializations associated with junctions. Intermediate filaments occur around the nucleus, as a layer at the base of the cell, and adjacent to desmosome-like junctions with germ cells. Intermediate filaments, together with microtubules, are also abundant in regions of the cell involved with the transport of SER, in cytoplasm associated with elongate spermatids, and in processes that extend into the residual cytoplasm of germ cells. Our observations of ultrastructure are consistent with the hypothesis that Sertoli cell microtubules are involved with the movement of germ cells within the seminiferous epithelium, and further implicate these structures as possibly playing a role in the retraction of residual cytoplasm from germ cells and the intracellular transport of SER. The abundance and organization of intermediate filaments suggest that these cytoskeletal elements may also be involved with events that occur during spermatogenesis.
地松鼠（侧纹黄鼠）是季节性繁殖动物，对其支持细胞进行了光镜和电镜检查，并将其结构，特别是细胞骨架的组织，与精子发生过程中曲细精管上皮内发生的事件联系起来。所考虑和描述的事件包括长形精子细胞的顶端移动、生殖细胞残余细胞质的退缩、支持细胞基部和顶端之间滑面内质网（SER）的运输以及精子释放。这些事件在该物种中非常明显，因为曲细精管上皮很薄，即生殖细胞很少，而且生殖细胞和支持细胞都很大。地松鼠的支持细胞具有非常发达的细胞骨架。微丝遍布整个细胞，但在与连接相关的外质特化中最为明显。中间丝出现在细胞核周围、细胞基部的一层以及与生殖细胞的类桥粒连接相邻处。中间丝与微管一起，在参与SER运输的细胞区域、与长形精子细胞相关的细胞质以及延伸到生殖细胞残余细胞质中的突起中也很丰富。我们对超微结构的观察与以下假设一致，即支持细胞微管参与曲细精管上皮内生殖细胞的移动，并进一步暗示这些结构可能在生殖细胞残余细胞质的退缩和SER的细胞内运输中发挥作用。中间丝的丰富程度和组织表明，这些细胞骨架成分也可能参与精子发生过程中发生的事件。
