Response of blastocyst–endometrium interactions in albino rats to sublethal doses of biological and synthetic insecticides

► A large number of rural workers is exposed to insecticide in Brazil Decis (deltamethrin) and XenTari®. ► Women constitute approximately 60% of the agricultural workforce in Brazil. ► Analyze the effects of sublethal doses XenTari® and deltamethrin on the blastocyst–endometrium interaction rats. ► Both insecticides interfered in the implantation process. The present study compared morphological, histochemical and histomorphometric characteristics of the sublethal effects of XenTari® and deltamethrin in blastocyst–endometrium interactions in female rats. Pregnant rats received 185, 1850 and 3700mg of XenTari® or 1.0, 2.0 and 4.0mg of deltamethrin (all doses per kg of body weight) and were sacrificed on the seventh day of pregnancy. The rats treated with the higher doses of insecticides exhibited a significant reduction in the number of implantation sites, vacuolated trophoblast cells, rare cytotrophoblasts, accentuated leukocyte infiltration, increase in vascularization of sites and blood in the uterine lumen. The decidua was more fibrous, particularly in the rats treated with the highest dose of XenTari®. In conclusion, sublethal doses of both XenTari® and deltamethrin produced qualitative/quantitative alterations in the blastocyst–endometrium interaction in female rats, thereby compromising the implantation process. Further studies are needed particularly at verifying the effects of these insecticides in the pregnancy to term in rats, order to investigate possible correlated effects on women working or living near agricultural fields.