Objective: To explore the effects of tanshinone and JAK2/STAT1 signaling pathway related mechanism in CVB3-induced myocarditis in murine.
Methods: A total of 110 inbred male Balb/c mice which were 4 to 6 weeks-old were randomly divided into five groups: normal control (N, n = 10), myocarditis control (C, n = 25), tanshinone group (T, 15 mg · kg⁻¹ · d⁻¹, i.p., n = 25), janus kinase 2 inhibitor AG490 group (A, 10 mg · kg⁻¹ · d⁻¹, i.p., n = 25), T+A group (H, n = 25). Myocarditis was induced by 0.5 ml 10(-9.51) TCID50/ml CVB3 i.p. injection for 10 days in group C, T and H. Myocardial histopathologic changes were observed and phospho-STAT1 expressions were detected by immunohistochemistry and Western blot analysis. The levels of serum cardiac troponin I were detected with chemiluminescence immunoassay.
Results: (1) Compared with group C, the histopathologic scores were significantly higher in group A and H (3.35 ± 0.57 and 3.34 ± 0.54 vs. 2.12 ± 0.39, P < 0.01), but lower in group T (1.40 ± 0.34 vs.2.12 ± 0.39, P < 0.01). (2) The expression of p-STAT1 protein was similar in group A and H compared to group N (P > 0.05), but was significantly lower than that in group C (0.017 ± 0.010 and 0.020 ± 0.010 vs. 0.246 ± 0.010, P < 0.01). The expression of p-STAT1 protein was significantly higher in group T than in group C (P < 0.01). (3) The levels of serum cardiac troponin I in group C, A, T and H were significantly higher than in group N ((0.42 ± 0.06), (1.17 ± 0.25), (0.23 ± 0.05) and (1.04 ± 0.19) µg/L vs. (0.02 ± 0.01) µg/L, all P < 0.01). The levels of serum cardiac troponin I were significantly higher in group A and H compared with group C ((1.17 ± 0.25) and (1.04 ± 0.19) µg/L vs. (0.42 ± 0.06) µg/L, P < 0.01), but were significantly lower in group T than in group C ((0.23 ± 0.05) µg/L vs. (0.42 ± 0.06) µg/L, P < 0.01). (4) There was a negative correlation between the expression level of p-STAT1 and the histopathologic scores (y = -4.503 x + 3.371, R² = 0.738, P < 0.01), but a positive correlation between the levels of serum cardiac troponin I and the histopathologic scores (y = 1.935x + 1.165, R² = 0.766, P < 0.01).
Conclusion: Tanshinone could attenuate myocardial injury via upregulating the JAK2/STAT1 signaling pathway in this murine viral myocarditis model.