Aflatoxin treatment brings about generation of multinucleate giant spermatids (symplasts) through opening of cytoplasmic bridges: Light and transmission electron microscopic study in Swiss mouse

Aflatoxins are dietary mycotoxins, which are a health hazard. Sub-symptomatic exposure to aflatoxins is known to produce male reproductive toxic effects with several manifestations. With a view to find if aflatoxins would produce multinucleate giant cells or symplasts in the seminiferous epithelium, we treated male Swiss mice with aflatoxin B1 for 35 days and subjected the testis to light and transmission electron microscopic analysis. We found abundant symplastic spermatids in the seminiferous epithelium of treated mice. The origin of these cells was traced to opening of cytoplamic bridges. Due to widening of cytoplasmic bridge, the cytoplasm of spermatid(s) in a clone entered a cytoplasm-rich spermatid, followed by the nucleus/nuclei. Subsequently, the bridge(s) collapsed resulting in spherical symplasts. The study, in addition to revealing yet another manifestation of aflatoxin-induced disruption of spermatogenesis, also provides first direct evidence for opening of cytoplasmic bridges as the mechanism underlying origin of spermatid symplasts.