[Effect of bone marrow mononuclear cell transplantation on miRNA-21 and miRNA-155 expression in mice with ulcerative colitis]

Objective: To investigate the effect of bone marrow mononuclear cell transplantation on the expression of miRNA-21 and miRNA-155 in mice with ulcerative colitis(UC). Methods: Healthy and clean KM mice aged 6-8 weeks were randomly divided into transplantation group, model group and normal control group with 15 mice in each group. In the transplantation group and model group, dextran sodium sulfate (DSS) was used to establish the model for 24 h. The mice in the transplantation group were injected with 0.4 ml of 4 ', 6-diaminol-2-phenylindole (DAPI) -labeled P3-BM-MNCs cell suspension (3.2×10(6) cells/ml), and the mice in the model group and the normal control group were injected with 0.4 ml phosphate buffer (PBS).UC disease activity index (DAI) was used to test the general condition of mice; HE staining was used to observe the pathological changes of colon tissue; Real-time quantitative PCR was used to detect the expression of miRNA-21 and miRNA-155 mRNA. Results: DAI scores of normal control group, model group and transplantation group were 0 (0,1), 3.1 (2.8,3.3) and 2.7 (2.4,3.1),respectively. Compared with normal control group, the DAI score of model group and transplantation group was higher (P<0.05), and the DAI score of transplantation group was lower than that of model group (P<0.05). The gross scores of tissue injury in normal control group, model group and transplantation group were 0 (0, 1), 3 (3, 4) and 1 (1, 2), respectively,and the pathological scores of tissue injury were 0 (0, 1), 16 (12, 16) and 6 (6, 8), respectively,compared with the normal control group. The tissue injury score of the model group and the transplantation group was higher (P<0.05), and the tissue injury score of the transplantation group was lower than that of the model group (P<0.05). The expression levels of miRNA-21 mRNA in normal control group, model group and transplantation group were 0.87±0.15, 2.38±0.29 and 1.59±0.32, respectively, and the expression levels of miRNA-155 mRNA were 1.87±0.46, 7.38±1.97 and 3.92±0.84, respectively, compared with the normal control group, the expression of miRNA-21 and miRNA-155 mRNA in the model group and transplantation group was higher (P<0.01), the expression of miRNA-21 and miRNA-155 mRNA in the transplantation group was lower than that of the model group (P<0.05). Conclusion: Bone marrow mononuclear cell transplantation can improve the histopathological and DAI scores of mice with UC, which may be related to the down-regulation of miRNA-21 and miRNA-155 mRNA expression.