Effect of chronic low dose of methotrexate on cellular proliferation during spermatogenesis in rats.

This study was conducted to evaluate cellular proliferation of germinal and non-germinal elements of seminiferous tubules following continuous Day 1 to Day 17 exposure of methotrexate (12.5 microgram) in male rats. There was significant decrease in the diameter of seminiferous tubules (P < 0.10) followed by increase of interstitial space (P < 0.01). The size of various stages of primary, secondary spermatocytes, and spermatids was altered significantly compared to controls. Vacuolization/decondensation of "chromatin-mass" in spermatocytes changed from rounded to oval. The size of the Sertoli and Leydig cells were reduced significantly. Basement membrane at some places seems to be disrupted and thin in experimental testis. Methotrexate induced cytotoxicity on the proliferation of cellular contents of seminiferous tubules elucidating the mechanism of dose-dependent drug induced testicular damage during spermatogenesis.