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

In our previous study, triphenyltin chloride (TPTCl) was found to induce im plantation failure, as preimplantation embryonic loss, in rats. In this stu dy, the effects of TPTCl on the uterine function, as a cause of implantatio n failure, were determined using pseudopregnant rats. Female rats were give n TPTCl 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. T he 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 pre vious study, these doses induced a significant increase in implantation fai lure in female rats given TPTCl on gestational day (GD) 0 to 3. The ovarian weight and number of corpora lutea in the TPTCl-treated groups were compar able to that of the controls. A significant decrease in serum progesterone levels after administration of TPTCl was found at 4.7 and 6.3 mg/kg. These findings suggest that implantation failure due to TPTCl may be mediated via the suppression of uterine decidualization and correlated with the reducti on in serum progesterone levels.