Relationship Between ANP,CNP In Follicular Fluid And Embryo Development And Pregnancy Outcome In Assisted Reproductive Technology

Introduction:Follicular growth and oocyte maturation are central components necessary for fertilization to occur and embryonic development.The composition of follicular fluid reflects the physiological status of the oocyte,and follicular fluid analysis is expected to be an important tool to evaluate the quality and developmental potential of oocytes.The presence of immunoreactive atrial natriuretic peptide(ANP)and C-type natriuretic peptide(CNP)has been confirmed in the follicular fluid of many female animals,and ANP and CNP were also present in human follicular fluid,but the correlation between follicular fluid ANP and CNP levels and embryonic development and pregnancy outcome remains unclear.In this study,we analyzed the relationship of ANP and CNP with embryonic development and pregnancy outcome,providing indicators for embryonic development and pregnancy outcome.Method:From Dec 2016 to Aug 2017,follicular fluid was collected from patients who underwent IVF/ICSI at the Reproductive Center,First Affiliated Hospital,Nanchang University.The patients were divided into 4 groups according to whether they were younger than 35 years old and whether they were pregnant: <35 years old pregnancy group,≥35 years old pregnancy group,<35 years old non-pregnant group.The protein expression levels of ANP and CNP in human follicular fluid were determined by ELISA double antibody sandwich method.The differences in ANP,CNP among different groups,and the differences in the ratio of normal fertilization,cleavage rate and the optimal embryo rate among subgroups were compared.Logistic regression and receiver operating characteristic curve(ROC)were applied to predict the outcome of pregnancy by ANP and CNP.Results:A total of 113 cycles were included in this study.The mean age of the included patients was 31.46±4.71 years old,the infertility years were 4.94±3.26 years,and the concentrations of ANP and CNP in follicular fluid were 25.66±6.33 and 106.17±32.38pg/ml,respectively.A total of 39 patients were successfully pregnant after treatment.The ANP concentration in the pregnant group was 27.66±6.06pg/ml,which was significantly higher than that in the non-pregnant group(24.61±6.25pg/ml).In addition,the rate of fertilization and fine embryo in the pregnant group was significantly higher than that in the non-pregnant group.Further stratified analysis of different age groups showed that in patients <35 years old,the ANP concentration of pregnant women was 27.76±5.85pg/ml,which was significantly higher than that of non-pregnant women(24.12±6.33pg/ml).The concentration of CNP in pregnant group was significantly lower than that in non-pregnant group(105.49±26.80 vs.118.57±26.55pg/ml,p=0.036).The fertilization rate and fine embryo rate of the pregnant group were 81.2%(320/394)and 56.3%(180/320),respectively,which were significantly higher than that of the non-pregnant group(72.5%(485/669)and 48.7%(236/485).There were no significant differences in follicular fluid ANP,CNP,fertilization rate,cleavage rate and fine embryo rate between pregnant group and non-pregnant group in patients aged ≥35 years.Logistic regression analysis of predictors of successful pregnancy in patients younger than 35 years showed that follicular fluid ANP concentration(OR: 1.177;95% CI: 1.067-1.298;p=0.001)was an independent predictor of successful pregnancy in patients <35 years of age,while increased follicular fluid CNP concentration(OR: 0.970;95% CI: 0.949-0.991;p=0.006)was a predictor of non-pregnancy.ROC curve analysis showed that the AUC valua(area under the curve)of follicular fluid ANP level for predicting pregnancy outcome in patients(<35 years old)was 0.71(95%CI: 0.56-0.80)with a sensitivity and specificity of 80% and 59%,respectively.whereas the AUC of follicular fluid CNP level for predicting pregnancy outcome was 0.62(95% CI:0.49-0.74)with a sensitivity and specificity of 30% and 93%,respectively.The sensitivity and specificity were 30% and 93%,respectively.Conclusion:Follicular fluid ANP and CNP expression levels were associated with different pregnancy outcomes in women,especially in young patients aged <35 years,and elevated follicular fluid ANP expression levels were an independent predictor of successful pregnancy in patients,whereas elevated follicular fluid CNP concentrations were a predictor of non-pregnancy.Furthermore,the mechanism of action of ANP and CNP in follicular fluid was related to oocyte quality and may promote embryo development.