Suppression of uterine decidualization as a cause of implantation failure induced by triphenyltin chloride in rats

In our previous study, triphenyltin chloride (TPTC1) was found to induce implantation failure, as preimplantation embryonic loss, in rats. In this study, the effects of TPTC1 on the uterine function, as a cause of implantation failure, were determined using pseudopregnant rats. Female rats were given TPTC1 by gastric intubation at 3.1, 4.7, and 6.3 mg/kg on pseudopregnant day (PPD) 0 to PPD 3 and the decidual cell response was induced on PPD 4. The uterine weight on PPD 9 served as an index of uterine decidualization. A significant decrease in the uterine weight, which indicates suppression of the uterine decidualization, was detected at 4.7 and 6.3 mg/kg. In our previous study, these doses induced a significant increase in implantation failure in female rats given TPTC1 on gestational day (GD) 0 to 3. The ovarian weight and number of corpora lutea in the TPTC1-treated groups were comparable to that of the controls. A significant decrease in serum progesterone levels after administration of TPTC1 was found at 4.7 and 6.3 mg/kg. These findings suggest that implantation failure due to TPTC1 may be mediated via the suppression of uterine decidualization and correlated with the reduction in serum progesterone levels.