Protective effect of MAPK signaling pathway mediated by ITGB3 gene silencing on myocardial ischemia-reperfusion injury in mice and its mechanism.

OBJECTIVE

To explore the effect of integrin β3 (ITGB3) gene silencing mediated mitogen-activated protein kinase (MAPK) signaling pathway on myocardial ischemia-reperfusion injury (MIRI) in mice.

MATERIALS AND METHODS

MIRI mice model was established, and myocardial tissues of MIRI mice and sham operation group mice were extracted. Hematoxylin-Eosin (HE) staining was used to observe the pathological changes of myocardial tissue; terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining was used to detect the apoptosis of myocardial cells; ELISA method was used to detect the levels of interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF)-α in the two groups. The infarct size was measured by TTC staining. Myocardial cells of MIRI model mice were isolated and cultured, and then grouped and transfected. The cells were transfected with the grouping of MIRI group, negative control (NC) group, MAPK signal pathway agonist Anisomycin group, MAPK signal pathway inhibitor SB203580 group, ITGB3-siRNA group, SB203580 + ITGB3-siRNA group. Real-time quantitative polymerase chain reaction (qRT-PCR) and Western blot were used to detect the mRNA and protein expressions of ITGB3, p38MAPK/p-p38MAPK, GSK-3β/p-GSK-3β, Cx43/p-Cx43, pro-apoptotic factor Bax and anti-apoptotic factor Bcl-2. 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay was used to detect cell proliferation and flow cytometry to detect cell apoptosis.

RESULTS

The expression of ITGB3 in myocardial tissue of MIRI mice was significantly higher than that of sham operated mice (p<0.05). Compared with the sham operation group, the apoptosis rate of myocardial cells in MIRI group was significantly increased, the expression levels of IL-1, IL-6 and TNF-α were significantly increased, and the myocardial infarction area was significantly increased (all p<0.05). Compared with MIRI and NC groups, ITGB3 mRNA and protein expression levels in ITGB3-siRNA group and SB203580 + ITGB3-siRNA group were significantly decreased (all p<0.05), but no significant change was found in Anisomycin group and SB203580 group (p>0.05). Furthermore, ITGB3-siRNA group and Anisomycin group had markedly decreased mRNA and protein expressions of ITGB3 and Bax, increased mRNA and protein expressions of p38MAPK/p-p38MAPK, GSK-3β/p-GSK-3β, Cx43/p-Cx43 and Bcl-2, as well as increased cell proliferation and decreased cell apoptosis (all p<0.05); SB203580 group indicated an opposite result with Anisomycin group; while SB203580 + ITGB3-siRNA revealed none significant statistical difference. In addition, compared with ITGB3-siRNA group, SB203580 + ITGB3-siRNA group showed significantly upregulated mRNA and protein expressions of Bax, downregulated mRNA and protein expressions of p38MAPK/p-p38MAPK, GSK-3β/p-GSK-3β, Cx43/p-Cx43 and Bcl-2, as well as decreased cell proliferation and increased cell apoptosis (all p<0.05).

CONCLUSIONS

Silencing ITGB3 gene expression can promote the activation of MAPK signaling pathway, elevate the phosphorylation of GSK-3β and Cx43 in the downstream, promote the proliferation of mouse myocardial cells, inhibit myocardial cell apoptosis and inflammatory reaction, and thus have protective effect on MIRI in mice.