Attenuating effects of selenium and zinc against hexavalent chromium-induced oxidative stress, hormonal instability, and placenta damage in preimplanted rats

As a toxic metal, hexavalent chromium (CrVI) has effects on both the reproductive and endocrine systems. This study aimed to evaluate the protective effects of selenium (Se) and zinc (Zn) against the toxicity of chromium on the placenta in pregnant Wistar albino rats. Thirty pregnant Wistar rats were divided into control and four treated groups, receiving subcutaneously (s.c) on the 3rd day of pregnancy, K2Cr2O7 (10 mg/kg body weight (bw)) alone, or in association with Se (0.3 mg/kg bw), ZnCl2 (20 mg/kg bw), or both of them simultaneously. Plasma steroid hormones, placenta histoarchitecture, oxidative stress profile, and developmental parameters were investigated. These results showed that K2Cr2O7 exposure induced a significant increase in the levels of both plasma estradiol (E-2) and placenta malondialdehyde (MDA), the number of fetal resorptions, and percent of post-implantation loss. On the other hand, K2Cr2O7 significantly reduced developmental parameters, maternal body and placenta weight, and plasma progesterone (P) and chorionic gonadotropin hormone (beta HCG) levels. However, K2Cr2O7 significantly decreased the placenta activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), reduced glutathione (GSH), and nonprotein sulfhydryl (NPSH). These changes have been reinforced by histopathological evaluation of the placenta. Se and/or ZnCl2 supplementation provoked a significant improvement in most indices. These results suggest that the co-treatment with Se or ZnCl2 strongly opposes the placenta cytotoxicity induced by K2Cr2O7 through its antioxidant action.