Our results demonstrated that the expression of MALAT1 has a higher level, while miR-144 expression significantly reduced in myocardial tissue after MI and also in left anterior descending (LAD)-ligation mice.
Collagen content and cross linking were determined by hydroxyproline and pyridinoline assays, MI size and scar thickness were measured post PicoSirius Red staining, and cardiac function was evaluated by echocardiography. miR-144 KO mice developed normally with normal cardiac function, however after MI, infarction size was greater and scar thickness was reduced in miR-144 KO mice compared with WT littermates. miR-144 KO mice had a lower incidence of acute cardiac rupture compared with WT littermates early after MI but there was impaired late remodeling, reflected by increased total cardiac collagen content and collagen cross-linkage associated with changes in Zeb1/LOX1 axis, and decreased left ventricular ejection fraction.
C57BL/6 mice were subjected to MI by permanent left anterior descending artery (LAD) ligation. miR-144 was delivered by intravenous injections of 8 mg/kg, 16 mg/kg, or 32 mg/kg at day 0, day 1, day 3, and then a similar dose given once every 3 days, until day 28 after MI.