Feasibility analysis of establishing endometriosis model by decidua tissue implantation

Objective To explore the expression characteristics of placental growth factor (PLGF), estrogen receptor (ER) -α and ER-β in decidua tissue, and to provide a theoretical basis for the establishment of endometriosis (EMS) model. Methods From August 2016 to February 2017, a total of 101 women in Second Affiliated Hospital of Nantong University were selected as research subjects. Under the aseptic condition, a total of 38 cases of decidua tissue were obtained from 38 pregnant women of caesarean section, 31 cases of eutopic endometrium and 37 cases of ectopic endometrium were obtained from 37 cases of EMS patients (including 31 cases with hysteromyoma), and 26 cases of normal endometrium were obtained from 26 cases of hysteromyoma patients. Immunohistochemistry and quantitative real-time polymerase chain reaction (qPCR) were used to detect the positive expression rate and mRNA relative expression levels of PLGF, ER-α and ER-β in these 4 types of endometrium tissues. The positive expression rate and mRNA relative expression levels of 3 factors in decidua tissue were statistically compared with those in other 3 endometrial tissues, respectively. All subjects in this study signed informed consents. Results ①The results of immunohistochemical staining showed that the positive expression rates of PLGF, ER-α and ER-β in decidua tissue (86.8%, 84.2%, 78.9%) were all higher than those in eutopic endometrium (61.3%, 58.1%, 38.7%), ectopic endometrium (54.1%, 35.1%, 48.6%) and normal endometrium (57.7%, 53.8%, 38.5%), respectively, and all the differences were statistically significant (χ2=6.003, 5.849, 15.298; χ2=9.723, 18.812, 7.469; χ2=6.996, 7.041, 10.796, all P<0.05). ②The results of qPCR detection showed that the mRNA relative expression levels of PLGF, ER-α and ER-β in decidual tissue [(2.60±0.26), (2.22±0.23), (2.05±0.31)], were all higher than those in eutopic endometrium [(1.23±0.09), (1.08±0.13), (0.95±0.14)], ectopic endometrium [(1.96±0.22), (0.38±0.06), (1.50±0.35)] and normal endometrium [(1.00±0.13), (1.00±0.11), (1.00±0.14)], respectively, and all the differences were statistically significant (t=21.243, 15.263, 15.382; t=9.939, 20.093, 8.112; t=20.532, 15.628, 17.282; all P<0.001). Conclusions Decidua tissue has strong planting characteristics which are helpful to the formation of ectopic lesions, and it provides a good carrier for the establishment of EMS model. Key words: Decidua; Placenta growth factor; Estrogen receptor alpha; Estrogen receptor beta; Endometriosis; Female