Apoptosis as a mechanism of germ cell loss in elderly men.

In comparison with other mammals, human spermatogenesis is known to be an inefficient process, of which germ cell degeneration is a normal part. This study was performed to determine the mechanism of cell death in the testes of elderly men. Testes from 20 patients undergoing orchidectomy for prostate cancer were fixed, sectioned and processed for the detection of apoptosis using the in situ end-labelling technique. In addition, the formation of DNA ladders, a hallmark of apoptosis, was also investigated. Occurrence of apoptosis was not confined to a particular germ cell population but comprised all types of germ cells. Sertoli cell apoptosis was not encountered. The numbers of degenerating germ cells were determined per standard reference area, but no significant relationship was found between the mean values and age or testis weight. Analysis of the median values for germ cell death per reference area suggested that apoptosis occurs in clusters within the testis but is a rare occurrence outside these areas. It is concluded that spontaneous apoptosis can mediate germ cell death in a variety of cell types in the aged human testis.