To investigate the expression and correlation of Notch1 protein and peroxisome proliferator-activated receptor (PPAR)-γ protein in placenta of early onset severe preeclampsia ( PE ) pregnant women.

From October 1, 2016 to September 30, 2017, 65 pregnant women with severe PE who were hospitalized in Guangdong Women and Children′s Hospital and underwent elective cesarean section were selected into this study. According to different gestational ages, 33 pregnant women with early onset severe PE (gestational age≤34 weeks) were included into early onset severe PE group, and 32 pregnant women with late onset severe PE (gestational age>34 weeks) were included in late onset severe PE group. At the same time, 30 pregnant women who were hospitalized in the same hospital due to abnormal fetal position or fetal distress and underwent elective cesarean section during the same period were randomly selected into control group. Immunohistochemically streptavidin peroxidase (SP) method was used to detect the distribution and expression levels of Notch1 protein and PPAR-γ protein in placental tissues. One-way ANOVA was used to compare the age, gestational age, average gray-value scale of Notch1 protein and PPAR-γ protein among three groups. The least significant difference (LSD) method was used to further compare the average gray-value scale of Notch1 protein and PPAR-γ protein among three groups. Pearson correlation analysis was used to analyze the correlation between Notch1 protein and PPAR-γ protein in placenta tissue of pregnant women. The procedures followed in this study were in accordance with the ethical standards established by the Human Subjects Trial Committee of Guangdong Women and Children′s Hospital, and this study was approved by this committee (Approval No. 201601027). Informed consent was obtained and signed with each subject.

①There were no significant differences in age and gestational age between early onset severe PE group, late onset severe PE group and control group (P>0.05). ② Notch1 protein was expressed in placental tissues of 3 groups, mainly localized in the cytoplasm of placental trophoblast cells, showing pale yellow-dark brown granules. PPAR-γ protein is mainly located in the nucleus of villous cytotrophoblast, and a small part of PPAR-γ protein is expressed in cytoplasm, presenting tan-dark brown granules. ③ The average grey-scale values of Notch1 protein and PPAR-γ protein in placental tissues among 3 groups were all statistically significant (F=5.565, P=0.012; F=8.694, P=0.006). Multiple comparison results showed the following results. The average gray-scale values of Notch1 protein in placenta tissues of 3 groups were respectively pairwise compared, and the differences were statistically significant (early onset severe PE group vs late onset severe PE group: LSD-t=3.218, P=0.005; early onset severe PE group vs control group: LSD-t=4.832, P=0.007; late onset severe PE group vs control group: LSD-t=2.948, P=0.008). The average grey-scale values of PPAR-γ protein in placental tissues were compared among 3 groups, and the differences were also statistically significant (early onset severe PE group vs late onset severe PE group: LSD-t=3.412, P=0.003; early onset severe PE group vs control group: LSD-t=4.927, P=0.002; late onset severe PE group vs control group: LSD-t=3.168, P=0.001). ④Pearson correlation analysis of Notch1 protein and PPAR-γ protein in placenta tissues of early severe PE group and late severe PE group showed that the average gray-scale values of Notch1 protein and PPAR-γ protein were negatively correlated (r=-0.461, P<0.05).

The relative expression level of Notch1 and PPAR-γ protein in placental tissue of pregnant women with early onset severe PE were down-regulated and up-regulated, suggesting that abnormal expressions of Notch1 protein and PPAR-γ protein may play a leading role in the infiltration of trophoblasts and affect the occurrence and development of early onset severe PE.