Effect of Exposure to Mixture of Heavy Metals Arsenic, Cadmium and Lead on Reproductive Function and Oxidative Stress in Female Rats

Abstract

Background : Toxicological consequences arising from exposure to mixtures of heavy metals especially at low, chronic and environmentally relevant doses are poorly recognised. In the present study, we evaluated effects of chronic exposure to combinations of three metals arsenic (As), cadmium (Cd) and lead (Pb) present frequently in drinking water on reproductive function and oxidative damage caused to reproductive organs of female rats. Method : Female rats were exposed to mixture of metals (As, Cdand Pb) for 90 consecutive days. The gain in body weight and weight of reproductive organs were recorded following autopsy on 91 stday. The oestrus cycle were monitored during entire treatment period. Numbers of corpora lutea, implantation sites, live fetus and survival of the fetus were evaluated in rats mated successfully with untreated male after completion of their respective treatment. Ovarian cholesterol, protein, ascorbic acid and enzyme Δ 5 -3β HSD levels were estimated. Serum levels of steroid hormones oestrogen and progesterone were estimated. Histopathological picture of both ovary and uterus were assessed. Levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidise (GPX) activity, amount of reduced glutathione (GSH) and malondyaldehyde (MDA) in blood, ovary and uterus were measured as biomarkers of oxidative stress. Results : The treated rats showed reduced body weight gain and reduction in the weight of ovary and uterus. Oestrus cycle was disrupted with continuous diestrous in treated animals. Number of corpora lutea, implantation sites and live fetus and the survival of fetus evaluate were reduced significantly in treated groups. The levels of ovarian cholesterol and ascorbic acid increased in treated rats with decrease Δ5 -3β HSD level. There was reduction in serum level of both the ovarian steroid hormones oestrogen and progesterone. The protein levels did not differ between the groups. There was a significant increase in levels of MDA and decrease in levels of all the antioxidant enzymes in treated group. Conclusion : The results revealed there was disruption to reproductive functions with decrease in stereoidogenic activity and associated oxidative stress in female rats treated with combination of mixture of metals (Cd, As and Pb) at low dose for 90 consecutive days.