The establishment of the endometrial receptive state,the implantation of activated blastocysts,and the decidualization of the uterine stroma are essential conditions for successful implantation in mammals and play decisive roles for subsequent pregnancy outcomes.The Wnt signaling pathway is associated with a variety of key functions such as proliferation,differentiation,apoptosis,and regeneration.During the embryo implantation,the Wnt signaling pathway plays an indispensable role.Studies have shown that the abnormal expression of Wnt signaling pathway can lead to endometriosis,endometrial cancer,and other reproductive diseases that seriously affect human health and quality of life.In this article we summarize the roles of Wnt signaling pathway in the establishment of uterine receptivity,blastocyst activation,embryo implantation,and decidualization and its regulatory mechanisms.

Objective: To investigate the association of ambient fine particulate matters (PM_2.5) exposure with anxiety in middle-aged and elderly people in China. Methods: Using a stratified random sampling method, 5 997 middle-aged and elderly people (aged 40-89) who resided in the region for more than 2 years and had no hearing or language impairment were selected from 32 districts/counties in the key areas for air pollution prevention and control in China from October 10^th, 2017 to February 7^th, 2018. Information about demographic characteristics, socioeconomic factors and health status were collected by questionnaire survey and physical examination. The anxiety symptoms were assessed by 7-item Generalized Anxiety Disorder Scales. Three-year moving average concentrations of PM_2.5 were calculated to estimate exposure level. The multivariate logistic regression model was conducted to assess the association between PM_2.5 exposure and anxiety. The interaction of age, gender, overweight, education, smoking, drinking and chronic diseases was also analyzed by likelihood ratio test. Results: There were 2 995 (49.94%) males subjects, 4 092 (68.23%) subjects with education of secondary school or above and 2 576 (42.95%) subjects with self-reported chronic diseases among the 5 997 middle-aged and elder participants. The prevalence of anxiety was 6.64% (n=398). The mean±SD of 3-year moving average concentrations of PM_2.5, O₃ and SO₂ were (53.50±13.38), (90.58±13.26) and (40.29±12.56) μg/m³, respectively. PM_2.5 had significantly association with anxiety, and the corresponding OR value was 1.17 (95%CI: 1.05,1.31) with a 10 μg/m³ increment of 3-year moving average concentrations of PM_2.5. Compared with female (OR (95%CI)=1.07 (0.93,1.23)), those with no chronic diseases (OR (95%CI)=1.06 (0.93,1.20)) and those with primary school degree or below (OR (95% CI)=0.90 (0.75,1.09)), the association between PM_2.5 and anxiety was stronger among male (OR (95%CI)=1.35 (1.12,1.63)) and those with chronic diseases (OR (95%CI)=1.77 (1.31,2.38)), middle school education (OR (95%CI)=1.43 (1.22,1.67)), college education and above (OR (95%CI)=1.68 (1.05, 2.67)), all the P interaction values were <0.05. Conclusion PM_2.5 exposure has significantly positive association with anxiety. The associations are stronger in male, people with higher educational qualifications and patients with chronic diseases.