Roles of progesterone on suppression of uterine decidualization and implantation failure induced by triphenyltin chloride in rats

ABSTRACT  In our previous studies, an administration of triphenyltin chloride (TPTCl) at 4.7 or 6.3 mg/kg on days 0–3 of pregnancy caused implantation failure, and the same doses of TPTCl on days 0–3 of pseudopregnancy caused a suppression of uterine decidualization correlated with a reduction in serum progesterone levels in rats. This study was conducted to determine the roles of progesterone on the TPTCl‐induced suppression of uterine decidualization and implantation failure in rats. Although lower uterine weight was found in hormone‐maintained ovariectomized rats given TPTCl at 4.7 or 6.3 mg/kg on days 0–3 and induced decidual cell response on day 4, no statistical significance in the uterine weight was detected between the control group and the TPTCl‐treated groups. The pregnancy rate and number of implantations in the groups given TPTCl at 4.7 or 6.3 mg/kg on days 0–3 of pregnancy and progesterone on days 0–8 of pregnancy were significantly higher than those in the groups given TPTCl alone. No significant differences in these parameters were found between the control group and the groups given TPTCl and progesterone. It can be concluded that the TPTCl‐induced suppression of uterine decidualization is mediated, at least partially, via the ovarian hormones, and that progesterone protects against the TPTCl‐induced implantation failure.