Ellagic acid inhibits the formation of hypertrophic scars by suppressing TGF‐β/Smad signaling pathway activity

Hypertrophic scar (HS) is a benign fibroproliferative skin disease, which lacks the ideal treatment and drugs. Ellagic acid (EA) is a natural polyphenol that prevents fibroblasts from proliferating and migrating. This study aimed to determine the role of EA in HS formation and its possible mechanism by in vitro experiments. HS fibroblasts (HSFs) and normal fibroblasts (NFs) were separated from HS tissue and normal skin tissue, respectively. HSFs were treated with 10 and 50 μM EA to assess their effect on HS formation. In particular, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and scratch assay were used to detect the viability and migration ability of HSFs. Quantitative reverse transcriptase real-time polymerase chain reaction was used to measure the mRNA expression level of basic fibroblast growth factor (bFGF), extracellular matrix (ECM)-related gene collagen-I (COL-I), and fibronectin 1 (FN1) in HSFs. Finally, Western blot was utilized to measure the expression level of TGF-β/Smad signaling pathway-related proteins in HSFs. The viability of HSFs was significantly increased compared with NFs. 10 and 50 μM EA treatment markedly inhibition the cell viability and migration of HSFs. EA treatment upregulated the bFGF expression level and downregulated the COL-I and FN1 expression level in HSFs. In addition, p-Smad2, p-Smad3, and transforming growth factor (TGF)-β1 expression levels as well as p-Smad2/Smad2 and p-Smad3/Smad3 ratios remarkably decreased in HSFs after EA treatment. EA inhibited the formation of HSs by suppressing the viability and migration of HSFs and ECM deposition as well as by preventing the activation of TGF-β/Smad signaling.