The Optimal Intervention Time of Bone Marrow Mesenchymal Stem Cells in Ameliorating Cardiac Fibrosis Induced by Viral Myocarditis: A Randomized Controlled Trial in Mice

Figures

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  Figure 1. Histological findings of myocardial tissues after BMSCs transplantation. The scale bars are equal to 100 μm in all of the images. (a) Control group. Histological findings of myocardial tissues in 4 weeks after PBS intraperitoneal injection. The myocardium was arranged neatly with clear contours and no obvious inflammatory cell infiltration (H&E, ×200). (b) VMC, the myocarditis group. Histological findings of myocardial tissues within 4 weeks after CVB3 intraperitoneal injection. The myocardium was disordered and showed residual inflammatory infiltration and necrotic lesions (H&E, ×200). (c–f) The BMSCs treatment subgroups. Histological findings of myocardial tissues within 4 weeks after CVB3 intraperitoneal injection. Mice in the VMC1d + BMSCs, VMC3d + BMSCs, VMC1w + BMSCs, and VMC2w + BMSCs subgroups were injected with BMSCs (1 × 106 cells of each mouse with 100 μl PBS) into their tail vein on the 1st day, 3rd day, 1st week, and 2nd week after they were infected by CVB3, respectively. The myocardium showed clear contours and no obvious inflammatory cell infiltration (H&E, ×200).

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  Figure 2. (a) The figure presented the myocardial inflammation pathological scores in different groups and subgroups. The difference among the groups was not statistically significant. (b) The collagen volume fraction of myocardial tissues. AP < 0.05 when compared to the control group; BP < 0.05 when compared to the VMC group; CP < 0.05 when compared to the VMC1d + BMSCs subgroup; and DP < 0.05 when compared to the VMC3d + BMSCs subgroup.

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  Figure 3. (a–f) Myocardial tissue collagen (blue) fiber staining results (Masson's trichrome staining, ×200, scale bar = 100 μm). (a) Control group. Histological findings of myocardial tissues in 4 weeks after PBS intraperitoneal injection. (b) VMC, the myocarditis group. Histological findings of myocardial tissues within 4 weeks after CVB3 intraperitoneal injection. (c–f) The BMSCs treatment subgroups. Histological findings of myocardial tissues within 4 weeks after CVB3 intraperitoneal injection. Mice in the VMC1d + BMSCs, VMC3d + BMSCs, VMC1w + BMSCs, and VMC2w + BMSCs subgroups were injected with BMSCs (1 × 106 cells of each mouse with 100ul PBS) through their tail vein on the 1st day, 3rd day, 1st week, and 2nd week, respectively, after they were infected by CVB3.

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  Figure 4. Quantification of col1α1 and col3α1 mRNA levels. (a) The relative expression of col1α1 mRNA in myocardial tissue. In 4 weeks after injection of CVB3, the expression of col1α1 mRNA was higher in the VMC group than in the BMSCs treatment subgroups. (b) The relative expression of col3α1 mRNA in myocardial tissue. The expression of col1α1 mRNA was higher in the VMC group than in the BMSCs treatment subgroups. n = 8 for each group. ∗P < 0.05 when compared to the control group; #P < 0.05 when compared to the VMC group.

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  Figure 5. The expression of the TGF-β1 signaling pathway related to protein in the myocardium with BMSCs treatments. (a) The expression levels of Smad2, p-Smad2, and TGF-β1 in the myocardium were analyzed by Western blotting. (b–d) Quantitative data of Smad2, p-Smad2, and TGF-β1 in the myocardium. n = 8 for each group. ∗P < 0.05 when compared to the control group; #P < 0.05 when compared to the VMC group; and ##P < 0.01 when compared to the VMC group.