Abstract

The testis of pre-pubertal and those of mature adult albino rats were physically divided into three segments with a view to studying histologically the gross structure and distribution of spermatogonia-derived cells (spermatogonia,spermatocytes, spermatids and mature spermatozoa) in the seminiferous tubules in these segments.  After using 50% Mezo stain (organic), spermatogonia-derived cells were manually counted on slide-view. A mixed population of dense uninucleated single or paired type A-like spermatogonia was clearly identifiable in both upper and lower segments as well as in the middle segment of the testis of pre-pubertal rats. In the mature adult rat testis, a mixed population of spermatocytes, oval spermatids and mature spermatozoa, in addition to a mixed population of dense uninucleated and multinucleated type A-like spermatogoniawere identified in seminiferous tubules of all three segments. However, there were larger numbers of clump-forming spermatogonia-like cells in the middle segment of the testis than in other segments in mature adult rats. A ratio of 2:1:1 for middle, upper and lower segments respectively was manually determined. These results suggest that the middle segment of the mature adult albino rat testis contains a highly enriched population of both single and multinucleated A-type spermatogonia-like cells and may be most suitable site for the harvesting of these cells.

Key words: Rat, pre-pubertal, testis, spermatogonia, spermatogenesis, mezo stain.