Identification of male germ cells undergoing apoptosis in adult rats

• Published in: Journal of reproduction & fertility Vol. 105; no. 1; pp. 25 - 33
• Main Authors: Brinkworth, M H, Weinbauer, G F, Schlatt, S, Nieschlag, E
• Format: Journal Article
• Language: English
• Published: England Society for Reproduction and Fertility 01.09.1995
• Subjects: Acetates - pharmacology; Animals; Apoptosis - drug effects; Follicle Stimulating Hormone - blood; Gonadotropin-Releasing Hormone - analogs & derivatives; Gonadotropin-Releasing Hormone - antagonists & inhibitors; Gonadotropin-Releasing Hormone - pharmacology; Male; Rats; Rats, Sprague-Dawley; Spermatogenesis; Spermatozoa - cytology; Spermatozoa - drug effects; Spermatozoa - physiology; Staining and Labeling; Testis - anatomy & histology; Testis - drug effects; Testosterone - blood
• DOI: 10.1530/jrf.0.1050025
• ISSN: 1470-1626; 0022-4251

The possible role of apoptosis in spontaneous or induced germ cell death was investigated by treating adult male rats with either a GnRH antagonist (112.5 μg kg −1 day −1 for 14 days) or methoxyacetic acid (650 μg kg −1 ; single dose) or sham-treated with either of the vehicles ( n = 3 per group). The antagonist virtually abolished gonadotrophin secretion, while methoxyacetic acid reduced serum testosterone concentrations and slightly increased those of FSH (neither significantly). Bands of low molecular mass characteristic of apoptotically degraded DNA were detected by electrophoresis in both treatment groups but not in the controls. Sectioned, Carnoy-fixed testes were screened for degenerating cells with periodic acid–Schiff's base and haemalaun or examined for apoptotic cells using a modified in situ end-labelling procedure. Periodic acid–Schiff's-stained dying cells were found in low numbers in control animals with a distribution and frequency that matched that of apoptotic cells. Degenerating germ cells identified by histology were present at certain stages of spermatogenesis after 2 weeks of antagonist treatment. A comparison of their distribution with that of end-labelled cells identified the cell death as apoptotic. Methoxyacetic acid caused a massive depletion of spermatocytes at stages IX-II, which was also found to be apoptotic. It is concluded that spontaneous germ cell death in adult rats is apoptotic and that both gonadotrophin ablation and administration of methoxyacetic acid can cause apoptosis in the germ cells of adult male rats, but via different routes.