Research Paper Volume 11, Issue 15 pp 5368—5388

Downregulation of microRNA-218 is cardioprotective against cardiac fibrosis and cardiac function impairment in myocardial infarction by binding to MITF

Figure 10. The effect of downregulation of miR-218 and MITF on the cardiac function and fibrosis in MI rats. a refers to the MI + miR-218 inhibitors + siRNA-NC group and b refers to the MI + miR-218 inhibitors + siRNA-MITF group. (A) the LVEF and LVFS of rats detected by ultrasonic cardiogram, n = 12; (B) the LVSP, LVEDP, +dp/dt max and -dp/dt max of rats detected by hemodynamic monitoring, n = 12; (C) the ratio of heart to body weight, n = 6; (D) serum levels of LDH and CPK examined by the biochemical analyzer, n = 6; (E) HE staining showing pathological changes of cardiac tissues (× 200), n = 3; (F) ultrastructure of cardiomyocytes observed by transmission electron microscope (× 5000), n = 3; (G) TTC staining showing the infarct size of rats, n = 3; (H) TUNEL staining showing the apoptotic index of cardiomyocytes (× 400), n = 3; (I) Western blot assay showing protein levels of apoptosis-related factors Bax and Bcl-2 in cardiac tissues, n = 3; (J) Masson staining showing the cardiac fibrosis of rats (× 200); (K) immunohistochemical staining showing the expression of type I collagen and type III collagen (× 200); (L) MVD and MMVD of cardiac tissues; (M) the mRNA and protein expression of angiogenesis-related factor VEGF detected by RT-qPCR and western blot assay; (N) the levels of MDA and the activity of GSH-Px and SOD determined by the spectrocolorimetric method, n = 3; (O) the mRNA expression of IL-1β, IL-6 and TNF-α detected by RT-qPCR, n = 3; (P) the serum levels of IL-1β, IL-6 and TNF-α detected by ELISA, n = 6; Data were analyzed by t test. MI, myocardial infarction; LVEF, left ventricular ejection fraction; LVFS, left ventricular fraction shortening; LVSP, left ventricular systolic pressure; LVEDP, left ventricular end diastolic pressure; RT-qPCR, reverse transcription quantitative polymerase chain reaction; MITF, microphthalmia-associated transcription factor; miR-218, microRNA-218; LDH, lactate dehydrogenase; CPK, creatine phosphokinase; MVD, microvascular density; MMVD, mean microvessels diameter; VEGF, vascular endothelial growth factor; ELISA, enzyme-linked immunosorbent assay; IL-1β, interleukin-1β; IL-6, interleukin-6; TNF-α, tumor necrosis factor-α; MDA, malondialdehyde; GSH-Px, glutathione peroxidase; SOD, superoxide dismutase.