Abstract: 463

QUANTITATIVE ANALYSIS OF SPERMATOGENESIS IN THE COMMON MARMOSET (CALLITHRIX JACCHUS JACCHUS).

GF Weinbauer¹ , H Aslam¹ , H Krishnamurthy¹ , A Einspanier^{2 *}, K Hodges²
Institute of Reproductive Medicine of the University , Münster, Germany ¹
German Primate Centre, Department of Reproductive Biology, Göttingen, Germany ²

Whereas a number of quantitative investigations on germ cell production have been conducted on human and Old-World monkey testes, such information is lacking for New-World monkeys. In the present work, germ cell production and apoptosis were analysed in testes of the common marmoset, a New-World nonhuman primate species frequently used in reproductive biology and toxiclogy studies. Bouin's-fixed tissue from 5 adult animals was plastic-embedded and sectioned at 25 m for stereological determination (optical disector) of testicular germ cell numbers. Other tissue pieces were snap-frozen for subsequent flow cytometrical analysis of cell numbers. Testes from another 6 adult animals were processed for in-situ end-labelling analyses of testicular apoptosis using flow cytometry on freshly prepared tissue and immunocytochemistry on Carnoy-fixed samples. Spermatogenesis was divided into 6 stages based on the criteria described for human spermatogenesis. Marmoset testes contained (mill./testis) 3±0.5 (SEM) type A- and 8±2 type-B spermatogonia, 48±6 pachytene spermatocytes, 102±19 round spermatids and 115±20 elongated spermatids. Following ajdustment of data for stage frequencies, the cell ratio for round spermatids:spermatocytes was >3 indicating no major germ cell loss during meiosis. Flow cytometric quantification of testicular apoptosis revealed little cell loss in haploid germ cells (< 2%) but >6% cell loss in spermatogonia, early spermatocytes and S-phase cells, indicating a high turn-over and proliferative activity of spermatogonial populations. Immunocytochemical localization of TUNEL-labeled cells confirmed these observations. This is the first quantitative description of spermatogenesis and germ cell yields in a New-World primate species. The findings suggest, that the common marmoset could provide a model for the study of primate spermatogonial proliferation and survival.

    This abstract is being presented on Tuesday, August 3 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.