Follistatin mitigates myofibroblast differentiation and collagen synthesis of fibroblasts from scar tissue around injured flexor tendons

Purpose: The aim of this study was to investigate the effect of FST gene on the inhibition of fibrosis in fibroblastic cells from scar tissue around repaired zone II flexor tendons. Materials and Methods: Immunohistochemistry was conducted on fibroblast cells transfected with adenovirus-LacZ (Ad-LacZ) as a marker gene (control), or with adenovirus-FST (Ad-FST) as a therapeutic gene. Fibroblast cultures without adenoviral exposure served as controls. Results: Fibroblastic cells transfected with Ad-FST demonstrated significant decrease in collagen type I, MMP-1, MMP2, and α-SMA mRNA expressions compared to those transfected with Ad-LacZ. In addition, fibroblastic cells transfected with Ad-FST exhibited significant decrease in MMP-1, TIMP-1, fibronectin, PAI-1, TRPV4, α-SMA, desmin, and PAX7 protein expressions. Conclusion: Based on these findings, we conclude that FST may be a novel therapeutic strategy for preventing scar adhesions around repaired tendons by inhibiting fibroblasts from differentiating into myofibroblasts, in addition to producing type I collagen and regulating extracellular matrix turnover via the downregulation of MMP-1 and TIMP-1. FST may also decrease contracture of the scar by inhibiting Ca²⁺-dependent cell contraction.