Stability of spermatogenic synchronization achieved by depletion and restoration of vitamin A in rats.
Stability of spermatogenic synchronization achieved by depletion and restoration of vitamin A in rats.
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通过大鼠体内维生素 A 的消耗和恢复实现生精同步的稳定性。
DOI：
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发表时间：
1990
影响因子：
3.6
通讯作者：
E. Nieschlag
中科院分区：
文献类型：
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作者：
J. Bartlett;G. Weinbauer;E. Nieschlag
对维生素A缺乏后精子发生同步的研究表明，这可能为研究精子上皮内激素作用和蛋白质分泌的阶段依赖性变化提供了一种体内模型。然而，到目前为止，还没有关于这种情况的稳定性或持久性的信息。在这项研究中，来自40只大鼠（包括对照组）的200个精管根据其在停药和补充维生素A后的生精阶段进行分类。在15周的停药和随后的补充维生素A后，精子发生以同步方式开始。这种同步在精子上皮的10个周期（2.5个生精周期）中保持稳定。随着维生素A缺乏时间的延长，一定比例的小管（30%）表现出仅支持细胞或支持细胞加精原细胞的形态特征，偶有厚质精原细胞。在本研究的11周观察期内，未观察到小管损伤比例的显著变化。睾丸睾酮浓度虽然与对照组相比有所升高，但与观察到的精细胞上皮周期阶段无关，而垂体和血清促卵泡激素水平升高，可能是由于观察到的受损小管的数量。维生素A治疗后精子发生的持续同步性表明，该模型适用于睾丸内旁分泌作用的研究。然而，随着时间的推移，同步率的下降可能提供了证据，表明精原上皮周期的各个阶段的持续时间可能受时间变化的影响，导致该模型系统中精子发生的渐进式不同步。
Studies of synchronization of spermatogenesis following vitamin A deficiency have suggested that this may provide an in vivo model for the study of stage-dependent changes in hormonal action and protein secretion within the seminiferous epithelium. However, until now, no information on the stability or durability of this condition has been available. In this study, 200 seminiferous tubules from each of 40 rats (including controls) were classified according to their spermatogenic stage after withdrawal and replenishment of vitamin A. Following 15 wk withdrawal and subsequent replenishment of vitamin A, spermatogenesis was initiated in a synchronous fashion. This synchrony remained stable for more than 10 cycles of the seminiferous epithelium (2.5 spermatogenic cycles). In association with the extended period of vitamin A deficiency, a proportion of tubules (30%) showed morphological characteristics of either Sertoli cells only or Sertoli cells plus spermatogonia with occasional pachytene spermatocytes. During the 11-wk period of observation in this study, no significant change in proportions of damaged tubules were observed. Testicular testosterone concentrations, although elevated with respect to controls, showed no correlation with the stage of the cycle of the seminiferous epithelium observed, whereas pituitary and serum follicle-stimulating hormone levels were elevated, probably due to the number of damaged tubules observed. The persistence of synchrony in spermatogenesis following vitamin A treatment suggests that this model is applicable for studies of paracrine actions within the testis. However, the decreased ratio of synchrony observed with time may provide evidence that duration of the individual stages of the cycle of the seminiferous epithelium might be subject to temporal variation, leading to a progressive desynchronization of spermatogenesis in this model system.