Kurohmaru M, Kobayashi H, Hattori S, Nishida T, Hayashi Y
Department of Veterinary Anatomy, Faculty of Agriculture, University of Tokyo, Japan.
J Anat. 1994 Dec;185 ( Pt 3)(Pt 3):503-9.
Spermatogenesis and acrosomal formation in the musk shrew, Suncus murinus, were studied by light and transmission electron microscopy. The cycle of the seminiferous epithelium was divided into 13 stages based on the characteristics of acrosomal change and nuclear shape, appearance of meiotic figures, location of spermatids, and period of spermiation. The relative frequencies of stages 1 to 13 were 5.1, 5.9, 10.1, 8.8, 12.5, 11.5, 10.6, 7.9, 6.0, 4.8, 8.9, 3.1 and 4.8, respectively. Additionally, spermatid development was subdivided into 13 steps. Acrosomal formation during spermiogenesis in the musk shrew was quite characteristic. However, in contrast to other mammalian species, the nucleus remained in the middle region of the seminiferous epithelium, and only the acrosome extended towards the basement membrane, beginning at step 7. The extension of the acrosome was conspicuous and reached maximum at step 9. At that time, the tip of the acrosome extended nearly to the basement. The acrosome of maturing spermatids was about 3-fold longer than that of spermatozoa. Thereafter, the acrosome gradually shortened and became flat. The enormous fan-shaped acrosome was completely formed at step 13. The prominent extension and subsequent shortening and flattening of the acrosome in the musk shrew appears to be a unique process to form the enormous fan-shaped acrosome.
利用光学显微镜和透射电子显微镜对麝鼩（Suncus murinus）的精子发生和顶体形成进行了研究。根据顶体变化、核形态、减数分裂图像的出现、精子细胞的位置以及精子释放期等特征，将生精上皮周期分为13个阶段。1至13阶段的相对频率分别为5.1、5.9、10.1、8.8、12.5、11.5、10.6、7.9、6.0、4.8、8.9、3.1和4.8。此外，精子细胞发育可细分为13个步骤。麝鼩精子形成过程中的顶体形成具有相当的特征。然而，与其他哺乳动物物种不同的是，细胞核始终位于生精上皮的中部区域，只有顶体从第7步开始向基底膜延伸。顶体的延伸很明显，在第9步达到最大程度。此时，顶体尖端几乎延伸到基底。成熟精子细胞的顶体比精子的顶体长约3倍。此后，顶体逐渐缩短并变平。巨大的扇形顶体在第13步完全形成。麝鼩顶体明显的延伸以及随后的缩短和平化似乎是形成巨大扇形顶体的独特过程。
