Abstract
Precursor cells in the rapid recovery of Leydig cells after depletion by ethanedimethanesulfonate (EDS) injury to bilateral abdominal testes were examined immunohistochemically 8, 11, and 14 days after an intraperitoneal injection of EDS, 75mg/kg, 2 weeks after cryptorchidization. Compared with shamoperated rats, the repopulation of Leydig cells in cryptorchid rats was accelerated. Row-like arranged fusiform-shaped mesenchymal cells were found in peritubular regions of abdominal testes 14 days after EDS injection. At 11 days after injection, a significant increase of bromodeoxyuridine-incorporated nuclei was noted in peritubular mesenchymal cells of abdominal testes when compared with scrotal testes. In intertubular tissues, both attenuated mesenchymal cells in earlier stages and fusiform-shaped mesenchymal cells in later stages were actin-, desmin-, and vimentin-negative, and the cells later revealed marked pyronophilia. Therefore, division of peritubular mesenchymal cells seems to contribute somewhat to the rapid recovery of abdominal testes, although differentiation through cytoplasmic pyronophilia from a pool of mesenchymal stem cells give rise to the main part of new Leydig cell populations.
