To investigate the expression of Beclin2 in the placenta tissues of pregnant women with intrahepatic cholestasis (ICP) and its effects on trophoblasts.

Thirty women with ICP who were hospitalized and delivered in the Department of Obstetrics, Zhuzhou Central Hospital from March 2018 to March 2019 were enrolled.15 placental tissues of the women with mild ICP and 15 women with severe ICP were selected, and the other 15 normal pregnant women were selected as the control group. Immunohistochemistry was used to detect the expression of Beclin2 protein in placental tissues. In vitro cultured trophoblasts were divided into 0 μmol/L group (supplemented with saline) , 2 μmol/L group (supplemented with 2 μmol/L TCA) , 20 μmol/L group (supplemented with 20 μmol/L TCA) , and 100 μmol/L group (supplemented with 100 μmol/L TCA) . In the following experiment, a blank control group (cells without any treatment) , Si-NC group (cells were transfected with Si-NC) and si-Beclin2 group (cells were transfected with si-Beclin2) , TCA group (cells were transfected with 100 μmol/L TCA) , TCA+Si-NC group (cells were added with 100 μmol/L TCA and transfected with Si-NC) and TCA+si-Beclin2 group (cells were transfected with 100 μmol/L TCA and transfected with si-Beclin2) were set up, and CCK-8 was used to detect trophoblast proliferation.The mRNA expression of Beclin2 was detected by real-time PCR, trophoblast apoptosis was detected by flow cytometry, and the protein expression of Beclin2, LC3 and p62 in trophoblasts was detected by Western blot. One way ANOVA was used for comparison between multiple groups, and LSD-t test was used for pairwise comparison between groups. Comparisons between control, ICP mild, and ICP severe groups were performed by c² test, and pairwise comparisons between groups were performed by Bonferroni method.

Compared with healthy pregnant women, the positive rate and strong positive rate of Beclin2 protein in placenta tissue of mild ICP and severe ICP pregnant women (33.33%vs 86.67% and 93.33%, 13.33%vs 46.67% and 66.67%) were significantly increased (P < 0.05/3) . Compared with the 0 μmol/L group and the 2 μmol/L group, the proliferation ability of cells in the 20 μmol/L group and 100 μmol/L group at 24 h (0.53±0.04 and 0.56±0.04 vs 0.42±0.05 and 0.38±0.06) , 48 h (0.78±0.06 and 0.81± 0.06 vs 0.60±0.05 and 0.55±0.06) and 72 h (0.94±0.08 and 1.02±0.09 vs 0.73±0.07 and 0.68±0.08) and expression of p62 protein (1.17±0.12 and 0.98±0.08 vs 0.85±0.07 and 0.38±0.03) were all decreased (P < 0.05) . Expressions of Beclin2 (0.15±0.01 and 0.23±0.01 vs 0.46±0.05 and 0.58±0.04) , LC3Ⅱ/LC3Ⅰprotein (0.76±0.08 and 1.26±0.11 vs 1.87±0.15 and 2.24±0.19) and apoptosis rate [ (3.87±0.25) %and (4.35±0.32) % ratio (8.67±0.59) %and (26.19±1.27) %] were increased (P < 0.05) , and it was dose-dependent. Compared with the blank control group, trophoblast Beclin2 in the TCA group (0.25±0.03 vs 1.28±0.11) and LC3Ⅱ/LC3Ⅰprotein expression (1.41±0.12 vs 6.39±0.51) , cell apoptosis rate [ (2.53±0.17) % vs (28.67±2.08) %] were significantly increased, p62 protein expression (0.97±0.08 vs 0.53±0.04) was significantly decreased (P < 0.05) . Compared with TCA+si- NC group, trophoblast Beclin2 in the TCA+Si-Beclin2 (1.16±0.13 vs 0.37±0.04) and LC3Ⅱ/LC3Ⅰprotein expression (5.88±0.47 vs 2.35±0.24) and cell apoptosis rate [ (27.18±2.14) %vs (16.33±0.79) %] were significantly reduced, and p62 protein expression (0.48±0.04 vs 0.95±0.09) was significantly increased (P < 0.05) .

Beclin2 is highly expressed in ICP maternal placental tissues, and Beclin2 promotes trophoblast apoptosis after TCA treatment by upregulating the level of autophagy.