树鼩(Tupaia belangeri chinensis)精子发生的细胞学观察

CYTOLOGICAL OBSERVATION ON SPERMATOGENESIS IN THE TREE SHREW(Tupaia belangeri chinensis)

对8只成体树鼩的睾丸进行了精子发生的细胞学和动力学观察。精原细胞可区分为A型和已分化定向的B型。生精上皮周期可分为12个连续阶段,不同阶段典型的细胞组合可被辨认。各阶段的相对持续时间以阶段Ⅴ、Ⅵ、Ⅶ的比率最高,分别为11.43,18.88、15.44;阶段Ⅸ、Ⅹ最低,为3.78和3.87。A型精原细胞在各阶段的数量分布并不保持恒定,阶段Ⅵ—Ⅷ和阶段Ⅸ时,分别出现两次成倍增长。B型精原细胞和前细线期精母细胞与每100个足细胞之比的平均值,在阶段Ⅰ、Ⅴ、Ⅶ分别为28.89、76.98、196.91。精细胞经14步变态为成熟精子。精子形成过程中顶体发育的形态学变化及成熟精子的形态,与灵长类动物相比具有较多的类似之处;而同啮齿类动物相比,存在明显的形态差异。

Cytology and kinetics on spermatogenesis in testes from 8 adult tree shrews were investigated by PAS-H technique.It is possible to distinguish the sper-matogonia typs A from type B.The cycle of seminiferous epithelium is divided into 12 successive stages.Typical cell associations in different stages are discriminated.Type A sparmatogonia are present in all stages;type B in stages X-Ⅵ;prelcptotenc spermatocytes(Pl)occur during late stageⅥ;pachytene spermatocyes(P)begin at late stageⅪand disappear in stageⅫof next cyclc;the second meiosis takes place in stageⅫ.The spermatids undergo 14 steps of development during spermiogcnesis and the spermatozoa are mostly released in stageⅥ.The relative durations(%)ofⅤ.Ⅵ,Ⅶare the highest(11.43,18.88,15.44,respectively)andⅨ,Ⅹthe lowest(3.78 and 3.87).The quantitative distributions of type A in different stages are inconstant,and double in stagesⅥ-ⅦandⅨ.Average number of B and Pl per 100 Serloli cells in stagesⅠ,Ⅲ,Ⅴ,Ⅶare 28.89,37.26,76.98196.99,respectively.The morphology of acrosomic development and mature spermatids appear similar to those of primates,except that the nuclear surfaces of spermatids are much covered by headcap and Golgi zone in step 1 is unclear.