Abstract:

Abstract: Objective To study the protective effect of miR-208b on myocardial infarction mice. Method Construction of a mouse model of myocardial infarction. The mice were randomly divided into the model group ( MI group) , the empty body group ( Ad group without miR-208b antagomir ) , the experimental group ( miR-208b antagomir group with miR-208b antagomir) . The mice without ligation of anterior descending branch were selected as the sham operation group ( sham group) . Echocardiography was used to detect cardiac function, the expression of miR-208b was measured by qRT-PCR, the area of myocardial infarction was measured by TTC staining, the apoptosis of myocardial cells in the periphery of infarction was detected by TUNEL, and the expression of Bcl-2 and Bax in myocardial cells was detected by Western-blot. Result After 7 days of myocardial infarction, the expression of miR-208b in the MI group and the Ad group was significantly increased compared with the Sham group ( P<0. 05) ; The infarct area of the miR-208b antagomir group was significantly smaller than that of the MI group ( P<0. 05) ; The levels of LVEDd and LVESD in the MI group, the Ad group and the miR-208b antagomir group were significantly higher than those in the Sham group, while LVEF and FS were significantly lower ( P<0. 05) ; The levels of LVEDd and LVESD in the miR-208b antagomir group were significantly lower than those in the MI group, while LVEF and FS were significantly higher ( P<0. 05) ; The apoptosis rate of myocardial cells in the MI group, the Ad group and the miR-208b antigomir group was significantly higher than that in the Sham group ( P<0. 05) ; The apoptosis rate of myocardial cells in the miR-208b antigomir group of was significantly lower than that in the MI group( P<0. 05) ; The result of Western blot showed that the heart cells in the group of MI and Ad were significantly lower than those in the group of MI ( P<0. 05) . The expression of Bcl-2 and Bax in myocardial infarction mice was significantly down regulated ( P < 0. 05) . The expression of Bcl-2 in the miR-208b antiagor group was significantly up regulated ( P < 0. 05 ) and Bax was significantly down regulated ( P < 0. 05 ) . Conclusion miR-208b is highly expressed in myocardial infarction mice. Inhibiting the expression of miR-208b can reduce the area of myocardial infarction, inhibit the apoptosis of myocardial cells, and improve the cardiac function of mice, so as to play the role of heart protection.