SPONTANEOUS DEGENERATION OF TESTICULAR GERM-CELLS IN CONGENITALLY ATHYMIC NUDE-MICE OF 4 STRAINS - A LIGHT-MICROSCOPIC OBSERVATION

Many hormonal studies have demonstrated that the presence of thymic fa ctors affects testicular function, However, morphological studies on t he testis in the absence of thymic factors are very limited. In the pr esent study, seminiferous tubules of nude mice of four strains were li ght microscopically observed in order to investigate the effect of con genital athymia on germinal cell components. Testes obtained from cong enitally athymic nude mice of CD1, BALB/c-nu/nu, LASAT, and KSN strain s were fixed in Bouin's solution, dehydrated, and embedded in plastic. The samples were cut and their sections were stained with hematoxylin and eosin. The results showed that degeneration of testicular germ ce lls was focally observed in all four strains of athymic mice. The dege nerating morphology was characterized by karyopyknosis and karyolysis of immature germ cells. multinuclear giant cell formation, and severe depletion of epithelial components with remaining Sertoli cells and/or some spermatogonia, KSN nude mice showed the most severe degenerative changes among the four strains of nude mice examined. Their significa nt degenerative changes first appeared at 2 weeks of age. In contrast, CD1 nude mice showed very slight degenerative features even at 20 wee ks of age. BALB/c-nu/nu and LASAT nude mice had more degenerated epith elia than did CD1 nude mice; however, their significant degenerative c hanges were apparent at 20 but not at 10 weeks of age. Therefore, the severity and the onset of spontaneous degeneration and depletion of te sticular germ cells in congenitally athymic mice were different among the four strains examined.