Kinetics of spermatogenesis in the Indian desert gerbil, Meriones hurrianae (Jerdon): seminiferous epithelial cycle, frequency of stages, spermatogonial renewal and germ cell degeneration

Abstract

The present study provides information on the germ cell associations, the pattern of spermatogonial cell renewal, percentage frequency distribution of different cellular associations and germ cell degeneration in the adult gerbil, M. hurrianae. Based on the formation of acrosomal system and the development of the spermatids as visualized with PAS-hematoxylin, 15 steps of spermiogenesis were identified. The first 12 steps were associated with 12 stages, and the other three steps were between the first 6 stages. The relative frequency was maximal for stage VII (14.24) and minimal for stage VIII (4.38), indicating stage VII to be of the longest and stage VIII of the shortest duration. On the basis of their shape, size and nuclear morphology, 6 types (A0, A1, A2, A3 In and B) of spermatogonia were identified in the gerbil. A-type spermatogonia are oval in shape. From A1 and A3 spermatogonia, progressive heterochromatinization was evident. The A3-spermatogonia divide to give rise to In spermatogonia which are smaller than A-type cells. The B-type spermatogonia are derived from In-type cells and are round in shape. These divide to give rise to first generation primary spermatocytes. Spermatogonia divide at fixed stages during the CSE, and they exhibit 5 peaks of mitosis. A-type spermatogonia divide during stages VI, IX, XII and I. In- and B-Types divide during stages II and V respectively. During stages XII and I, A3-type cells divide to give rise to In- as well as to A1-type cells, thus restoring the A-spermatogonial population. In this way A3-cells serve to renew the stem cells.