Toyama Y, Itoh Y
Department of Anatomy, School of Medicine, Chiba University, Japan.
Andrologia. 1996 Mar-Apr;28(2):109-15. doi: 10.1111/j.1439-0272.1996.tb02765.x.
A boar with decapitated spermatozoa was examined. The growth rate and libido were normal. The right testis was in the scrotum, but the left one was intra-abdominal. Ejaculated spermatozoa and tissue specimen from both testes were observed by light and electron microscopy. Only tailless heads and headless tails of spermatozoa were observed in the ejaculate. The ratio of heads to tails was about 1:4. Motility of the headless tails was about 25%. The proximal extremity in the tail was occupied by the proximal centriole. The basal plate could not be found in the head or in the tail. Pathogenesis of decapitated spermatozoa in the present case was analysed by investigating spermiogenesis in the scrotal testis. Since the pair of centrioles failed to approach the nucleus, mechanical connection between the proximal centriole and the nucleus did not seem to be established. In addition, the basal plate was not formed on the nuclear membrane. Since the ratio of tailless heads to headless tails was also 1:4 in the testis, it was concluded that the heads had already detached the tails in the testis.
对一头精子头部与尾部分离的公猪进行了检查。其生长速度和性欲正常。右侧睾丸位于阴囊内，但左侧睾丸位于腹腔内。通过光学显微镜和电子显微镜观察了射出的精子以及来自双侧睾丸的组织标本。在射出物中仅观察到无尾的精子头部和无头的精子尾部。头部与尾部的比例约为1:4。无头尾部的运动能力约为25%。尾部的近端被近端中心粒占据。在头部或尾部均未发现基板。通过研究阴囊内睾丸的精子发生过程，分析了本病例中精子头部与尾部分离的发病机制。由于一对中心粒未能靠近细胞核，近端中心粒与细胞核之间似乎未建立机械连接。此外，核膜上未形成基板。由于睾丸中无尾头部与无头尾部的比例同样为1:4，因此得出结论，精子头部在睾丸内就已与尾部分离。
