Müller E, Rodriguez-Martinez H, Braden S, Edqvist L E
Department of Andrology, School of Veterinary Medicine, National University of Costa Rica.
Zentralbl Veterinarmed A. 1992 Jun;39(5):382-91. doi: 10.1111/j.1439-0442.1992.tb00195.x.
The testicular ultrastructure of sexually mature Zebu (Bos indicus) bulls from Costa Rica was studied in relation to their classification based on andrological examinations undertaken in the field. Based on the testicular consistency at palpation, each bull was assigned to one of three groups, ranging from normal (Group A) to markedly reduced testicular consistency (Group C). The ultrastructure of the clinically normal testicle (Group A) in the Zebu bull resembled that of Bos taurus. In testicles with a slight to moderate reduction of testicular consistency (Group B) degenerated primary spermatocytes and spermatids were common at all stages of the seminiferous cycle. Abnormalities in the condensation of the chromatin, acrosomal defects, and the presence of degenerated cells and cellular debris were the most common of disturbances found. In testicles from bulls with a marked reduction of testicular consistency (Group C) the seminiferous epithelium of most tubules showed degenerative changes, thereby making it impossible to classify the stage of the cycle. The changes were mainly restricted to spermatocytes and spermatids, whose relative numbers were reduced. The number of cells undergoing meiotic divisions was also greatly reduced. Changes in the spermatids were also found including the appearance of severe acrosomal defects, such as acrosomal pouches, the failure of nuclear elongation and clear defects in chromatin condensation. The present ultrastructural findings in Bos indicus do not differ from the picture of normal testicular structure and of testicular degeneration usually found in Bos taurus bulls.
对来自哥斯达黎加的性成熟瘤牛（Bos indicus）公牛的睾丸超微结构进行了研究，并与基于现场进行的雄性生殖系统检查的分类相关联。根据触诊时睾丸的质地，每头公牛被分为三组之一，从正常（A组）到睾丸质地明显降低（C组）。瘤牛公牛临床正常睾丸（A组）的超微结构与黄牛（Bos taurus）相似。在睾丸质地轻度至中度降低的睾丸（B组）中，在生精周期的所有阶段，退化的初级精母细胞和精子细胞都很常见。染色质凝聚异常、顶体缺陷以及退化细胞和细胞碎片的存在是最常见的干扰。在睾丸质地明显降低的公牛的睾丸（C组）中，大多数小管的生精上皮显示出退行性变化，因此无法对周期阶段进行分类。这些变化主要局限于精母细胞和精子细胞，其相对数量减少。进行减数分裂的细胞数量也大大减少。还发现精子细胞有变化，包括出现严重的顶体缺陷，如顶体袋、核伸长失败和染色质凝聚明显缺陷。瘤牛目前的超微结构发现与黄牛公牛通常发现的正常睾丸结构和睾丸退化情况并无不同。
