Fig. 2: The experimental grouping of animals and cells and the effect of miR-130a on activity and apoptosis of myocardial cells.

A We grouped the SD rats (male, 10 weeks, n = 12) and H9c2 cells, and showed the treating processes. The proximal left anterior descending (LAD) coronary artery of rats (n = 6) was ligated to induce myocardial ischemia for 45 min followed by reperfusion for 6 h in the I/R group, and the heart samples were obtained for experiments. The sham group’s SD rats (n = 6) underwent the same procedures but did not ligate LAD after threading. In groups of cells, to edit the gene expression, H9c2 cells were transfected with vectors, siRNA, or inhibitors. Next, to Simulate IRI in vitro, H9c2 cells were grown in Hanks’ balanced salt solution under 95% N₂ and 5% CO₂ for 45 min, then under 20% O₂ and 5% CO₂ while the medium was changed to DMEM re-oxygenating for 6 h in the Hypoxia-reoxygenation (HR) groups. H9c2 cells of the normoxia group were grown in DMEM under 20% O₂ and 5% CO₂. Heart tissue of rats and H9c2 cells of each group were collected for subsequent experiments. NC: negative control; OE: over-expression; KD: knockdown. Normoxia: cells grow under 20% O₂ and 5% CO₂. Hypoxia-reoxygenation: cells grow in Hanks’ balanced salt solution under 95% N₂ and 5% CO₂ for 45 min, then under 20% O₂ and 5% CO₂ in DMEM for 6 h. B, C Apoptosis in H9c2 cells was measured by Flow Cytometry under normoxia or HR conditions with miR-130a OE or miR-130a KD. n = 3 in each group. D Cell viability was determined by using a cell counting kit-8 under normoxia or HR conditions with miR-130a OE or miR-130a KD and absorbance was measured at 450 nm. n = 14 in the Ctrl NC and HR NC group; n = 16 in the Ctrl miR-130a OE, HR miR-130a OE, Ctrl miR-130a KD, and HR miR-130a KD group. Relative cell activity (%) = [(As-Ab)/(Ac-Ab)] ×100%. As: absorbance of the experimental group; Ab: absorbance of the blank group; Ac: absorbance of the Ctrl NC group. Data were expressed as mean ± SD by two-tailed Student’s t-test, ^*P < 0.05, ^**P < 0.01 vs. Ctrl NC; ^#P < 0.05, ^##P < 0.01 vs. HR NC. APC allophycocyanin, FITC Fluorescein Isothiocyanate.