Fig. 2: Direct injection of miR199a-5p mimics protects the heart from myocardial infarction.

a Experimental design: Assessment of short- and long-term post-MI cardiac function and morphology in rats receiving MSN package miR199a-5p mimics. Transmission electron microscopy photographs (scale bars: 200 nm) and percentage size distribution of MSN/miR199a-5p (n  =  3 independent samples). b Kaplan–Meier survival curves after injection of miR199a-5p mimics compared to injection of control mimic after MI injury, p value was generated by Log-rank (Mantel-Cox) test, n = 39 rats, mimic control; n = 31 rats, miR199a-5p mimics. c The echocardiographic images and echocardiography analyses of cardiac function after miR199a-5p mimic injection at indicated time points post-MI, (1 weeks: n = 30 rats, mimic control, n = 27 rats, miR199a-5p mimics; 4 weeks: n = 23 rats, mimic control, n = 27 rats, miR199a-5p mimics; 2 months: n = 22 rats, mimic control, n = 25 rats, miR199a-5p mimics; 4 months: n = 20 rats, mimic control, n = 25 rats, miR199a-5p mimics; 6 months: n = 11 rats, mimic control, n = 15 rats, miR199a-5p mimics; 8 months: n = 9 rats, mimic control, n = 10 rats, miR199a-5p mimics; 12 months: n = 8 rats, mimic control, n = 10 rats, miR199a-5p mimics). d–k Heart weight/tibial length (HW/TL) ratio and lung weight/body weight (LW/BW) ratio of rats after miR199a-5p mimic injection at 6 months (d, n = 6 rats, mimic control; n = 9 rats, miR199a-5p mimics) and 12 months (e, n = 8 rats, mimic control; n = 10 rats, miR199a-5p mimics). LV internal dimension at end-systole (LVID’s) at 6 months (f, n = 15 rats, mimic control; n = 20 rats, miR199a-5p mimics) and 12 months (g, n = 8 rats, mimic control; n = 10 rats, miR199a-5p mimics) post-MI, n = 6-10. Elisa detection of expression of pathological remodeling marker protein BNP in serum after miR199a-5p mimic injection at 6 months (h, n = 6 rats, mimic control; n = 9 rats, miR199a-5p mimics) and 12 months (i, n = 8 rats, mimic control; n = 10 rats, miR199a-5p mimics). Masson’s staining displayed the fibrous tissue (blue) and myocardium (red) of sections of hearts from rats at 6 months (j, n = 6 rats, mimic control; n = 9 rats, miR199a-5p mimics) and 12 months (k, n = 8 rats, mimic control; n = 10 rats, miR199a-5p mimics) post-MI. Scale bars: 1 mm. Statistical analysis of infarct size of the infarcted heart. Data for (c)–(k) are presented as mean ± SD. The p-values were generated using an unpaired two-tailed Student’s t-test. *P < 0.05, **P < 0.01, NS, not significant. Source data are provided as a Source Data file.