Morphofunctional disturbances of human sperm after incubation with organophosphorate pesticides

The organophosphorate pesticides are highly toxic for insects and mammals, but their effects in the male reproductive tract are scarcely known. Many a lterations induced by organophosphorate pesticides have been described such as: cytogenetic alterations in germinal cells, oligozoospermia and teratoz oospermia in the mouse. Parathion(R), the pesticide mostly utilized in Chil ean agriculture, is rapidly metabolized to paraoxon, the active metabolite, in mammalian organisms. The purpose of this study is to evaluate the effec t of Parathion(R) and paraoxon on different morphological and functional pa rameters of the sperm. Human spermatozoa were incubated with Parathion(R) a nd paraoxon at different concentrations (0.05, 0.1, 0.2, 0.4 and 0.8 mM). V itality (tripan blue and eosin tests), acrosome reaction (triple stain test ), plasma membrane integrity (HOS-test), and chromatin stability (sodium th ioglycolate test) were determined. The observations were done by optical mi croscopy at 1000x of magnification and three hundred sperms were evaluated for each treatment. The results indicated that Parathion(R) and paraoxon increase the percent o f sperm with acrosome reaction and also increase the percentage of sperm wi th chromatin decondensation in a dose-dependent manner. The vitality and pl asma membrane integrity decrease significantly in a dose-dependent manner. The results suggest a direct action of Parathion(R) and paraoxon on the dif ferent parameters studied. The morphofunctionality of sperm is altered sign ificatively, suggesting that Parathion(R) and paraoxon, thanks to their alk ylating and electrophylic properties, could act on DNA and proteins respect ively, to elicit these changes.