Effect of quercetin on the expression of Bcl-2/Bax apoptotic proteins in endometrial cells of lipopolysaccharide-induced-abortion mice

OBJECTIVE： To explore the effect of quercetin on the expressions of Bcl-2/Bax apoptotic proteins in endometrial cells in mice with abortion induced by lipopolysaccharide.METHODS： For in vivo experiment, twenty five Kunming mice were randomly divided into five groups at day 4 of pregnancy, with 5 mice per group. The mice were treated with lipopolysaccharide（LPS）through tail vein intravenous injection at day 4 of pregnancy, followed by different concentrations of quercetin by oral gavage consecutively at days 5 to6 of pregnancy. On day 7 of gestation, the mice were sacrificed and the histopathological changes of the uterus tissues were observed. Immunohistochemical staining was applied to the detection of Bcl-2/Bax apoptotic proteins in the endometrial cells. For in vitro experiment, the primary endometrial cells werecultured using a uterus tissue mass culturing method sampled at day 4.5 of pregnancy. The cells were treated with LPS with or without different dosages of quercetin, respectively, for 12 h after 80% confluence. The expression of Bcl-2/Bax apoptotic proteins were detected by western blotting.RESULTS： Both the in vivo and in vitro experiments showed decreased expression of Bcl-2 and enhanced expression of Bax after LPS treatment, leading to a decreased Bcl-2/Bax ratio. The expression of Bcl-2 significantly increased while the expression of Bax was significantly elevated, in the LPS plus quercetin group compared to the LPS only group.CONCLUSION： These results suggest that quercetin has protective effect by partially regulating the expression of Bcl-2/Bax proteins, which in turn inhibits endometrial cell apoptosis and benefits the embryo implantation.