Russell L D, Clermont Y
Anat Rec. 1977 Mar;187(3):347-66. doi: 10.1002/ar.1091870307.
In normal adult rats some germ cells degenerate at several vulnerable steps of spermatogenesis. These are the type A spermatogonia, midpachytene spermatocytes, primary and secondary spermatocytes which degenerate during their respective maturation divisions and step 7 and 19 spermatitids. In the present study, these degenerating cells were examined under the electron microscope, and their frequency was determined in toluidine blue stained semithin sections of testes from normal, hypophysectomized (at 5.5 days after operation) and hypophysectomized rats injected with FSH and LH separately or in combination. With the exception of the step 19 spermatids, the degenerating germ cells underwent necrosis in vacuolated spaces delimited by Sertoli cells. In the case of the affected step 19 spermatids, an apical cytoplasmic process of the Sertoli cell initially ensheathed a long segment of their flagellum, and then each degeneration cell was drawn deep in the seminiferous epithelium where it was phagocytozed by the Sertoli cell. Soon after hypophysectomy the incidence of degenerating mid-pachytene spermatocytes, step 7 and 19 spermatids which are present in stages VII or VIII of the cycle of the seminiferous epithelium, increased significantly. In contrast the number of degenerating primary or secondary spermatocytes during the meiotic divisions seen in stage XIV of the cycle or of any other germinal cell was not significantly modified. While the injection of FSH alone had no influence on the number of degenerating cells in hypophysectomized rats, injections of LH at the two doses administered (0.7 microng or 20 microng) reduced significantly the number of degenerating cells seen in stages VII-VIII of the cycle; combined injections of FSH and LH (20 microng) reduced the number of these degenerating cells to the normal low values. Thus it appeared that the mid-pachytene spermatocytes and the step 7 and 19 spermatids, all present in the adluminal compartment of the seminiferous epithelium in stages VII or VIII of the cycle, were more sensitive to the presence of absence of gonadotropic hormones than the other germ cells present in the seminiferous epithelium.
在正常成年大鼠中，一些生殖细胞在精子发生的几个易损阶段会发生退化。这些细胞包括A型精原细胞、粗线期中期精母细胞、初级和次级精母细胞（它们在各自的成熟分裂过程中退化）以及第7和19步的精子细胞。在本研究中，在电子显微镜下检查了这些退化细胞，并在正常、垂体切除（术后5.5天）以及分别或联合注射促卵泡激素（FSH）和促黄体生成素（LH）的垂体切除大鼠睾丸的甲苯胺蓝染色半薄切片中确定了它们的频率。除了第19步的精子细胞外，退化的生殖细胞在由支持细胞界定的空泡空间内发生坏死。对于受影响的第19步精子细胞，支持细胞的顶端细胞质突起最初包裹其鞭毛的一段长节段，然后每个退化细胞被拉入生精上皮深处，在那里被支持细胞吞噬。垂体切除后不久，存在于生精上皮周期VII或VIII期的退化粗线期中期精母细胞、第7和19步精子细胞的发生率显著增加。相比之下，在周期XIV期减数分裂过程中退化的初级或次级精母细胞或任何其他生殖细胞的数量没有显著改变。虽然单独注射FSH对垂体切除大鼠中退化细胞的数量没有影响，但注射两种剂量（0.7微克或20微克）的LH显著减少了在周期VII - VIII期所见的退化细胞数量；联合注射FSH和LH（20微克）将这些退化细胞的数量减少到正常低值。因此，似乎在周期VII或VIII期存在于生精上皮管腔隔内的粗线期中期精母细胞以及第7和19步精子细胞比生精上皮中的其他生殖细胞对促性腺激素的存在或缺失更敏感。
