Effects of Slit2 on hypertrophic scar formation: an in vitro study in fibroblasts

Hypertrophic scarring (HTS) is a common complication of burns and has been associated with Slit2 protein. Slit2 plays various physiological and pathological roles in some body organs and tumors. However, its role in HTS development remains poorly understood. Therefore, this study investigated the involvement of intracellular and exogenous Slit2 in hypertrophic scar formation in vitro. Human normal fibroblasts (HNFs) and hypertrophic scar fibroblasts (HTSFs) were isolated from normal skin and hypertrophic scar tissues, respectively. Immunohistochemistry was conducted, and molecular expressions were detected by real-time polymerase chain reaction and western blotting. Cell proliferation and mobility were assessed. The results showed that Slit2 and Robo1 expressions were higher in the dermis of HTS tissues and HTSFs than in normal skin and HNFs. Downregulation of Slit2 expression by siRNA transfection reduced the expression of alpha-smooth muscle actin (α-SMA) and extracellular matrix in HTSFs. Additionally, treatment with recombinant Slit2 protein enhanced cell proliferation, expression of α-SMA, ECM, vimentin, N-cadherin, and migration by inducing the phosphorylation of both SMAD and non-SMAD signaling in HNFs. These findings highlight the active role of Slit2 in HTS formation, offer new insights into HTS pathology, and suggest Slit2 as a potential therapeutic target for post-burn hypertrophic scarring.