Imatinib attenuates cardiac fibrosis by inhibiting platelet-derived growth factor receptors activation in isoproterenol induced model

Figures

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  Fig 1. IMA reduces the ventricular wall thickness and cardiac hypertrophy caused by ISO. Mice were treated with vehicle, Imatinib (IMA, 40mg/kg/d, injected intraperitoneally everyday), Isoproterenol (ISO, 20mg/kg/d, injected subcutaneously everyday), IMA + ISO for 7 days. (A) The ventricular wall thickness was detected by M-mode echocardiography at day 8. (B) The early to late diastolic peak velocity (E/A) ratio was detected by Doppler echocardiography at day 8. (C) Hearts removed from one mouse in each group are shown. (D) The gravimetric analysis of heart weight to body weight (HW/BW) ratio. (n = 5–8 per group, **: p<0.01, ***: p<0.001).

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  Fig 2. Effects of IMA on the heart cells survival. (A) (B) Representative transferase-mediated dUTP nick-end labeling (TUNEL) staining (400×), and percentage of TUNEL positive cells in the hearts sections from mice treated with vehicle, IMA, ISO, IMA + ISO for one week are shown. Ki-67 was tested by immunohistologic analysis (400×). (C) (D) The percentage of Ki-67 positive cells in the hearts sections from mice treated with vehicle, IMA, ISO, IMA + ISO for one week are shown. (n = 5–8 per group, *: p<0.05, **: p<0.01). HPF: High Power Field.

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  Fig 3. IMA inhibits ISO-induced cardiac fibrosis. (A) Myocardial mRNA expression of collagen I and III was decreased in mice hearts treated with IMA + ISO compared with that in ISO treated mice hearts. (B) Histopathological features of collagen deposition by Sirius red staining of heart sections from mice model (100×), and quantification of sirius red staining. (C) The lysates of hearts tissue from mice treated with vehicle, IMA, ISO, IMA + ISO for one week were subjected to western blotting to analyze the expression of α-SMA, and quantitative analysis of the α-SMA expression. (n = 8 per group, *: p<0.05, **: p<0.01). (The Kruskal-Wallis test, followed by Dunn’s Multiple Comparison test, was used to perform statistical comparison for mRNA expression of collagen I.).

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  Fig 4. IMA reduces the expression of fibrosis related genes induced by ISO. (A) The protein expression of PDGF-A, PDGF-B, PDGF-C, and PDGF-D in hearts from mice treated with vehicle, IMA, ISO, IMA + ISO for one week was tested by Western blot. (B) The mRNA level of HGF, CCN2, and TGF-β1 in hearts from mice treated with vehicle, IMA, ISO, IMA + ISO for one week was tested by RT-qPCR. (n = 5–8 per group, *: p<0.05, **: p<0.01).

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  Fig 5. IMA inhibits the kinase activation of PDGFRs in mice heart tissue. (A) The mRNA expressions of PDGFRα and PDGFRβ in hearts from mice treated with vehicle, IMA, ISO, IMA + ISO for one week were tested by RT-qPCR. (B) The lysates of hearts tissue were subjected to western blotting to analyze the phosphorylation level of p-PDGFRα (Tyr720), and p-PDGFRβ (Tyr740), and the expression of PDGFRα, PDGFRβ, and MMP-9. The western results from one mouse in each group and statistical analysis of western blot bands are shown. (C) The mRNA expression of MMP-9 in hearts from four groups was tested by RT-qPCR. (n = 5–8 per group, *: p<0.05).

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  Fig 6. Effect of IMA in PDGF-AA treated mice cardiac fibroblasts. Mice cardiac fibroblasts were treated with PDGF-AA (10 ng/ml), IMA-0.5 (0.5 μM), IMA-1.0 (1.0 μM), PDGF-AA + IMA-0.5, and PDGF-AA + IMA-1.0 for 24 h. (A) The lysates were subjected for western blotting analysis the expression of p-PDGFRα, PDGFRα, and α-SMA. (B) Quantitative analysis of p-PDGFRα and α-SMA protein level. (C) The mRNA expression of collagen I and III. The data are representative of three independent experiments. (*: p<0.05).