Effects of Lilopristone on the Development of Embryo and Decidua in Rat

To investigate the mechanisms of lilopristone (ZK98.734) on anti-early pregnacy, we studied the effects of ZK98.734 on the development of embryo and endometrium /decidua in Sprague-Dawley rats. The results showed: (1) ZK98.734 (5mg/kg) could obviously inhibit embryo development. The size of embryo became smaller, part of the cells in the embryo appeared lysis and necrosis. (2) ZK98.734 (5mg/kg) could inhibit the development of endometrium /decidua of embryo in early pregnacy rats. Endometrium became thinner and lighter. the secretion of glands obviously decreased, the differentiation of interstitial cell was inhibited. These results suggested that ZK98.734 might play effects of anti-implantation and anti-early pregnacy by inhibiting the development of endometrium /decidua, following the progesterone receptor of endometrium was blocked in rats.