Role of interleukin-6 in cardiac fibroblasts proliferation and cardiac fibrosis

Aim: To observe the effect of interleukin-6 (IL-6) on proliferation and p27 expression in cardiac fibroblasts (CFs), and to explore the mechanism of IL-6 in CFs proliferation and cardiac fibrosis. Methods: Neonatal SD rats CFs were cultured as a model. Cell proliferation was evaluated with MTT assay, and cell cycle distribution and positive rate of p27 expression were determined with flow cytometry. Results: 1 The A value of CFs measured with MTT assay in IL-6 (1 × 10⁷ U/L, 48h) group(0.38 ± 0.01) was significantly higher than that in the basic condition group(0.32 ± 0.01) (t = -15. 983, P = 0.000); 2 The percentage of CFs in S stage[13.00 ± 3.53)%] and proliferation index (PI) [29.43 ± 1.94)%] in the IL-6 group were significantly higher than those in the basic condition group (7.45 ± 0.97)% and (26.03 ± 0.96)%] (t = -3. 036, P = 0.023; t = -3.142, P = 0.020), while the percentage of G0/G1 stage cells [(70.58 ± 1.94)%] was obviously lower than that in the basic condition group [(73.98 ± 0.98)%] (t = 3.142, P = 0.020); 3 Positive rate of p27 expression in the IL-6 group (72.60 ± 2.47 %] was significantly lower than that in the basic condition group[(78.45 ± 1.91)%] (t = 3.753, P = 0.009). Conclusion: IL-6 can induce CFs proliferation, and its mechanism may be related to the downregulation of p27 expression.