Abstract: Objective To investigate the possible role of basic fibroblast growth factor (bFGF) and transforming growth factor β1 (TGF-β1) in mice with Coxsackie viral myocarditis and their relationship. Methods Eighty male BALB/c mice, 4 weeks old, were divided randomly into study group (n=40) and control group (n=40). The study group was repeated intraperitoneally injected with Coxasckie viral B3 to establish the model of viral myocarditis, while the control group was injected with virus-free Eagle’s medium in the same period. On the 7th, 14th, 28th and 42th day after the first injection, 8 alive mice selected randomly from each group were sacrificed to examine the myocardial collagen volume fraction (CVF) by Masson dyeing, and to detect the protein and mRNA expression of bFGF and TGF-β1 by RT-PCR and immunohistochemistry. The correlations were analyzed. Results At each time point, the expressions of protein and mRNA of bFGF and TGF-β1 both in study group were significantly higher than those in control group (P<0.01), and gradually increased over time. The expressions of protein and mRNA of bFGF
and TGF-β1 were positively correlated with CVF (r=0.86~0.95, all P<0.01). In addition, the expressions of protein and mRNA of bFGF also had positive correlation with the expression of protein and mRNA of TGF-β1 (r=0.94, 0.92, P<0.01). Conclusion bFGF and TGF-β1 may promote the occurrence and development of myocardial fibrosis in viral myocarditis, which may provide a new target for future treatment of myocardial fibrosis.