Degeneration of the germinal epithelium in the mouse and rat testis with respect to the seminiferous cycle following ligation of the vasa efferentia.

The manner in which the cycle of the germinal epithelium is affected during progressive atrophy of seminiferous tubules, and the form of cellular degeneration that occurs at each stage of the cycle has been studied in adult rat and mouse testis following unilateral ligation of the vasa efferentia. Following the ligation, which was placed as close to the testis as possible, groups of animals were killed at postoperative periods ranging from 1 to 10 days for rats, and 16 hours to 7 days for mice. The stages of the cycle were identified by the periodic acid-Schiff-haematoxylin technique using the classification of Leblond and Clermont (1952) and Oakberg (1956a). The timing of the cycle did not appear to be disrupted by the degenerative changes that resulted: at all postoperative periods, the viable germ cells were associated with the same stages of the cycle as they are in the normal testis. The frequency with which each stage of the cycle occurred was measured in the ligated testis of the mouse and found to be unchanged from that established in the control testis. The atrophic reactions at each stage of the cycle followed a consistent and well-defined sequence of events which have been described in the form of a general scheme. The proposed scheme has not previously been described in the literature, and consists of 4 main steps in tubule degeneration. During stages I - IX of the cycle these steps are: (1) the "spermatid sloughing" stage, (2) the "multinucleated body" stage, (3) the "Sertoli cell cytoplasm" stage, and (4) the "Sertoli cell sloughing" stage. During stages X - XII of the cycle in the mouse (stages X - XIV in the rat), the first 2 of the 4 degenerative steps differ and have been termed: (1) the "cellular sloughing" stage, and (2) the "spermatocyte ghost cell" stage. Degeneration of seminiferous tubules affected Sertoli cells in a definite manner: the Sertoli cell nuclei increased in number, frequently migrated away from the basement membrane and were often sloughed into the tubule lumen. These changes in the behaviour of Sertoli cells during tubular atrophy are discussed.Science, Faculty ofZoology, Department ofGraduat