RESUMEN
Mercury induces structural and functional damage in several organs, however the effects of subtoxic doses of the metal on the male reproductive system are not well defined. In order to analyze testicular and epididymal morphological alterations and changes in IL-4 or IFN-gamma serum levels, adult male Sprague-Dawley rats received 0.01, 0.05 or 0.1 microg/ml of mercuric chloride (HgCl(2)) in deionized water for 1 to 7 months by oral route. Controls received deionized water alone. Twenty rats, separated in four groups of five animals each, were used per time of exposure. Progressive degenerative lesions consisting of lack of germ cell cohesion and desquamation, arrest at spermatocyte stage and hypospermatogenesis were observed in seminiferous epithelium by light and electron microscopy. Leydig cells showed cytoplasmic vacuolation and nuclear signs of cell death. Loss of peritubular cell aggregation was evidenced in the epididymis. Mercury accumulation was detected in both organs by mass spectroscopy. Rats showed enhanced IFN-gamma serum levels as compared to controls but only reached significance after 7 months of mercury administration. Subtoxic doses of inorganic mercury could lead to reproductive and immunological alterations. The results demonstrate that sublethal concentrations of mercuric chloride are enough to induce morphological and ultrastructural modifications in male reproductive organs. These contribute to functional alterations of spermatogenesis with arrest at spermatocyte stage, hypospermatogenesis and possibly impaired steroidogenesis which together could affect male fertility.