Figure 5: LCZ696 Suppresses MMP-9 Activity in the Infarcted Region 3 Days After MI

(A) Representative images of LV cross-sections with in situ zymography in the border area of the infarcted region 3 days after MI of the vehicle, enalapril, and LCZ696 groups. Scale bar = 200 μm (B). Semi-quantitative analysis of gelatinolytic activity showed significantly lower activity in the LCZ696 compared to the vehicle and enalapril groups. n = 7 per group. *p < 0.05, Bonferroni’s multiple comparison test. (C, D) Specific MMP-9 activity assay in the infarcted region 3 days after MI, showing no differences in (C) total MMP-9 among the vehicle, enalapril, and LCZ696 groups. However, (D) active MMP-9 was significantly lower in the LCZ696 compared to the vehicle and enalapril group. In these box-and-whisker plots, lines within the boxes represent median values; the upper and lower lines of the boxes represent the 75th and 25th percentiles, respectively; and the upper and lower bars outside the boxes represent maximum and minimum values within 1.5 times the interquartile range from the 75th and 25th percentile, respectively. n ≥ 24 per group. *p < 0.05, Bonferroni’s multiple comparison test. (E) Double immunofluorescence images showing co-localization of MMP-9-positive cells with F4/80-positive cells in the border area of the infarcted region 3 days after MI. Scale bar = 20 μm. DAPI = 4’, 6-diamidino-2-phenylindole; other abbreviations as in Figure 4.