Arrested apoptosis without nuclear fragmentation produced by efferent duct ligation in round spermatids and multinucleated giant cells of rat testis

The apoptotic process evoked by efferent duct ligation in the testes of adult rats was followed for 10 days by differential staining for haematoxylin-eosin, periodic acid-Schiff and a modified trichrome technique in optical microscopy and by ultrastructural localization of acid phosphatase. Round spermatids showed the first effects of efferent duct ligation. At day 3 after ligation, annular clumps of chromatin with typical apoptotic characteristics appeared against the nuclear membrane of these cells. Afterwards, membranous structures and a wide separation between the two layers of the nuclear membrane were observed but nuclear fragmentation did not occur and apoptotic granules were not seen. Cytoplasmic components were also altered, and severely damaged organoids and empty vacuoles lacking acid phosphatase reaction were frequently seen. On day 2 after efferent duct ligation, multinucleated giant cells appeared, which displayed similar characteristics as spermatids and showed no acid phosphatase reaction. Although abnormal spermatids and multinucleated giant cells were surrounded by the cytoplasm of Sertoli cells, neither lysosomal acid phosphatase nor phagocytic activity was detected. It is concluded that efferent duct ligation specifically affects round immature spermatids eliciting a partial nuclear apoptotic response that is not accompanied by autophagic or heterophagic activity and without lysosomal participation in Sertoli cells.