Effects of Metformin on the Cultured Eutopic Endometrial Cells From Endometriosis Patients

Objective To study effects of metformin on the cultured eutopic endometrial cells from patients with endometriosis (EMS). Methods From January to July 2012, a total of 50 samples from patients with EMS were included into study group. At the same time, another 88 samples form cases who were underwent operation because of cervical lesions, uterine septum, ovarian teratoma, ovarian cyst were included into control group. There were no significant differences on general information (eg. age) between two groups (P>0.05). The cell model was established. The cells were incubated without or with different concentration of metformin (1 μmol/L, 10 μmol/L, 100 μmol/L and 1 000 μmol/L) for 24 h, 48 h, 72 h, and the influence of eutopic endometrial cell prooliferation was detected by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT). The changes of cell cycle and cell apoptosis were observed by flow cytometry (FCM). Expressions of Bcl-2, Bax in the cells were measured by enzyme linked immunosorbent assay (ELISA) method. The study protocol was approved by the Ethical Review Board of Investigation of Xingtai People's Hospital. Informed consent was obtained from all participates. Results There was no significant difference between eutopic endometrial cell proliferation in control group incubated with or without metformin (1 μmol/L, 10 μmol/L, 100 μmol/L and 1 000 μmol/L). The proliferation of eutopic endomentrial cells of EMS patients were inhibited by metformin in a dose-dependent manner. The proliferation of eutopic endometrium cell incubated without or with metformin (1 μmol/L, 10 μmol/L, 100 μmol/L and 1 000 μmol/L) for 48 h, 72 h were significantly inhibited (P<0.05). The inhibition rate was highest after 1 000 μmol/L metformin (P<0.01). After intervention of metformin, eutopic endometrial cells in G1 phase were significantly higher than those of the control group (P<0.05). The expressions of Bcl-2 were all up-regulated after metformin treatment, while the expressions of Bax were all down-regulated. Conclusion Metformin can inhibit cell proliferation of eutopic endometrium of EMS, induce cell apoptosis and change its cell cycle's proportion. Key words: Metformin; Endometriosis; Endometrium; Cell proliferation; Apoptosis