Effect of imatinib on DOCA-induced myocardial fibrosis in rats through P38 MAPK signaling pathway

B. Dong, D.-F. Chen, X.-H. Bu, H.-B. Qin, Y. Xi

Department of Cardiology, Heping Hospital Affiliated to Changzhi Medical College, Changzhi, China. Dong1519@yeah.net

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• Cardiology

OBJECTIVE: To explore the role of imatinib in desoxycorticosterone acetate (DOCA)-induced myocardial fibrosis in rats by the p38 mitogen-activated protein kinase (MAPK) signaling pathway.

MATERIALS AND METHODS: Normal group (n=20), DOCA induction group (n=20), and imatinib treatment group (treatment group, n=20) were set up. Then, the cardiac function was examined via magnetic resonance imaging (MRI) and echocardiography (ECG) on the 21st d after modeling. Alkaline phosphatase (ALP) and myocardial function index creatine kinase-MB (CK-MB) were detected. The enzyme-linked immunosorbent assay (ELISA) was performed to measure tumor necrosis factor-gamma (TNF-γ) and interleukin-6 (IL-6). Hematoxylin-eosin (HE) staining assay was carried out to observe the pathological changes in myocardial tissues. Quantitative Polymerase Chain Reaction (qPCR) and Western blotting were employed to measure the expression levels of important myocardial fibrosis-related genes [checkpoint kinase 1 (Chek1) and alpha-smooth muscle actin (α-SMA)], as well as genes and proteins of the p38 MAPK signaling pathway.

RESULTS: In comparison with the normal group, DOCA induction group had significantly lowered fractional shortening (FS, %) and ejection fraction (EF, %), but overtly increased left ventricular end-diastolic dimension (LVEDd) and left ventricular end-systolic dimension (LVESd), as well as levels of serum ALP, alanine aminotransferase (ALT), and CK-MB. Besides, the levels of TNF-γ, IL-6, and IL-1β were notably raised in the DOCA induction group. HE staining results showed that myocardial injury was more severe in DOCA induction group. The results of the gene detection revealed that the expression levels of Chek1, α-SMA, p38 MAPK, and JNK were evidently higher in DOCA induction group than those in the imatinib treatment group (p<0.05), and the expression of p38 MAPK protein in the rat myocardial tissues was remarkably lower in the treatment group than that in the DOCA induction group (p<0.05).

CONCLUSIONS: Imatinib can regulate the repair of myocardial injury caused by DOCA-induced myocardial fibrosis in rats by repressing the p38 MAPK signaling pathway.

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