Department of Morphology, Tokai University School of Medicine, Isehara, Japan.
Am J Primatol. 2011 Jun;73(6):570-7. doi: 10.1002/ajp.20930. Epub 2011 Feb 1.
We performed histological analyses for comparing testicular microstructure between the gorilla, chimpanzee, and orangutan. Testicular samples were obtained by autopsy or biopsy from 10 gorillas, 11 chimpanzees, and 7 orangutans from several zoos and institutes. The seminiferous epithelia were thick in the chimpanzee and orangutan but thin in the gorilla. Leydig cells in the interstitial tissue were abundant in the gorilla. The acrosomic system was extremely well developed in the orangutans. Our study reveals that the cycle of seminiferous epithelium in orangutan testis can be divided into ten stages, whereas that in human, chimpanzee, and gorilla testes can be divided into only six stages. Phylogenetic analyses of the number of divisions may indicate that the seminiferous epithelium of our common ancestor has changed since the orangutan diverged from it. Furthermore, we performed comparative analyses of testicular microstructure to estimate relative sperm production among these three animals, and proposed a new indicator (namely the spermatogenic index, SI) closely related to sperm production. The SI indicated that a chimpanzee usually produces about 223 times more sperm than a gorilla and about 14 times more than an orangutan. Our data demonstrate the significance of the SI for estimating sperm production, thus aiding our understanding of the reproductive strategy as well as testis weight and relative testis size in investigated primates.
我们进行了组织学分析，比较了大猩猩、黑猩猩和猩猩之间的睾丸微观结构。睾丸样本取自几家动物园和研究所的 10 只大猩猩、11 只黑猩猩和 7 只猩猩的尸检或活检。在黑猩猩和猩猩中，精小管上皮较厚，而在大猩猩中则较薄。间质组织中的间质细胞丰富。在猩猩中，顶体系统发育良好。我们的研究表明，猩猩睾丸的生精上皮周期可分为十个阶段，而人类、黑猩猩和大猩猩睾丸的生精上皮周期仅可分为六个阶段。对分裂次数的系统发育分析可能表明，自猩猩与共同祖先分化以来，其生精上皮已发生变化。此外，我们还对睾丸微观结构进行了比较分析，以估计这三种动物的相对精子生成量，并提出了一个与精子生成密切相关的新指标（即精子发生指数，SI）。SI 表明，一只黑猩猩通常产生的精子比大猩猩多约 223 倍，比猩猩多约 14 倍。我们的数据表明，SI 对估计精子生成具有重要意义，从而有助于我们了解所研究灵长类动物的生殖策略以及睾丸重量和相对睾丸大小。
