Effects of thiacloprid, a neonicotinoid pesticide, on rat reproductive system: Pregnancy hormone disruption and abortion trends

Thiacloprid (TCL), commonly known as Biscaya, is among the most widely used pesticides in agriculture, designed to eliminate insects by targeting their nicotinic receptors. This study explores the effects of orally administering TCL (at a dose of 50 mg/kg) on the hormone secretion crucial for pregnancy and the factors influencing abortion throughout the early, middle, and late stages of pregnancy in female rats.

Following TCL exposure, there were significant increases in levels of 17β-Estradiol, prostaglandins F_2α and E₂, and serum oxytocin hormone in different stages of pregnancy. In contrast, progesterone and endothelin-1 serum levels notably decreased during the initial and final stages of pregnancy. Additionally, TCL led to a substantial rise in lipid peroxidation levels and a decrease in total thiol molecules and total antioxidant capacity, especially in uterine tissue. Although TCL did not significantly affect the morphological characteristics of the delivered fetuses, it notably increased the number of abortions, especially during the second and third stages of pregnancy.

In summary, our findings suggest that TCL elevates the risk of abortion in pregnant rats by disrupting the secretion of hormones crucial for fertility (such as 17β-Estradiol/progesterone) and by increasing the secretion of abortion-inducing hormones like prostaglandins and oxytocin. Furthermore, these effects may be associated with disruptions in the oxidant/antioxidant balance within the ovaries and uterus.