Induction of male germ cell apoptosis by testosterone withdrawal after ethane dimethanesulfonate treatment in adult rats.

OBJECTIVE

To carry out a detailed quantitative analysis of male germ cell apoptosis in seminiferous epithelium in a long period after EDS administration.

METHODS

The apoptosis in adult rat testes was induced by a single i.p. injection of ethane dimethanesulphonate (EDS) in a dose of 75 mg/kg body weight. The TUNEL assay for in situ detection of apoptosis and quantitation of apoptotic germ were performed in testicular sections days 1, 3, 7, 14, 21 and 35 after EDS treatment. Plasma levels of testosterone (T) and luteinizing hormone (LH) were measured by RIA.

RESULTS

First signs of seminiferous epithelium regression were manifested by a marked increase in the number of apoptotic cells on 3rd day after EDS treatment. The maximal value of germ cell apoptosis was established on 7th day post EDS that coincided with lowest T levels. Later, until the end of investigated period, the elevated values of all investigated parameters for quantification of germ cell apoptosis decreased, but remained still higher as compared to control and, in addition, also T concentrations returned to normal range and their mean values were lower than these in controls. The pachytene spermatocytes and spermatids were the predominant cell types that underwent apoptosis after EDS treatment.

CONCLUSIONS

Quantitative patterns of germ cell death after testosterone deprivation reveal in advance the kinetic of germ cell depletion and regeneration in a long period after EDS. These new findings bring additional support to the concept that germ cell apoptosis is a hormonally regulated process. Induction of germ cell apoptosis by EDS could be considered as a result of differential alterations occurring in the main testicular cell types, more than one pathway being probably involved in that physiological cell death in the testis.