In vitro Effects of Nerve Growth Factor on Cardiac Fibroblasts Proliferation, Cell Cycle, Migration, and Myofibroblast Transformation

Background: Recent research indicates that nerve growth factor (NGF) promotes cardiac repair following myocardial infarction by promoting angiogenesis and cardiomyocyte survival. The purpose of this study was to investigate the effects of NGF on cardiac fibroblasts (CFs) proliferation, cell cycle, migration, and myofibroblast transformation in vitro. Methods: CFs were obtained from ventricles of neonatal Sprague-Dawley rats and incubated with various concentrations of NGF (0, 0.01,0.1, 1, 10, and 100 ng/ml; 0 ng/ml was designated as the control group). Cell proliferation and cell cycle of the CFs were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry (FCM), respectively. A cell scratch wound model and transwell were carried out to observe effects of NGF on migration of CFs after 24 h of culture. Real-time polymerase chain reaction (RT-PCR) and Western blotting were used to measure a-smooth muscle actin (alpha-SMA) at mRNA and protein levels after CFs were incubated with various concentrations of NGF. Results: Expression of a-SMA measured by RT-PCR and Western blotting significantly increased in the 1 and 10 ng/ml NGF groups (P < 0.05). Absorbance values of CFs showed that NGF did not influence the proliferation of CFs (The A(490) values were 0.178 +/- 0.038,0.182 +/- 0.011, 0.189 +/- 0.005,0.178 +/- 0.010, 0.185 +/- 0.025, and 0.177 +/- 0.033, respectively, in the 0, 0.01, 0.1, 1, 10, and 100 ng/ml NGF groups [P = 0.800, 0.428, 0.981, 0.596, and 0.913, respectively, compared with control group]), and FCM analysis showed that the percentage of CFs in GO/G 1, S, and G2/M phases was not changed (P > 0.05). The cell scratch wound model and transwell showed that CFs migration was not significantly different (P > 0.05). Conclusion: NGF induces myofibroblast transformation but does not influence proliferation, cell cycle, or migration of CFs in vitro.