Abstract: Objective Hypertrophic scar （HS） is a common fibrotic skin disorder characterized by the activation of fibroblast and the excessive deposition of extracellular matrix（ ECM）. This study intends to explore the inhibitory effect of carnosol on HS. Methods  Human hypertrophic scar-derived fibroblasts （sHSFs） were treated with 5-80 µmol/L carnosol， and CCK-8 method was used to confirm the appropriate concentration of carnosol. Then HSFs were treated with 30 µmol/L carnosol and wound healing assay was used to detect migration ability of HSFs. Moreover， HSFs were treated with 10-30 µmol/L carnosol， qRT-PCR and western blot（ WB） were used to evaluate the effects of carnosol on mRNA and protein expression of collagen secretion and activation-related genes in HSFs. Rabbit ear scar model was established and treated with 10 µmol/L or 30 µmol/L carnosol until 14th day after surgery， on the 14th and 28th day after the establishment of model， samples were collected for HE and Masson’s trichrome staining to evaluate tissue structure， and α -SMA immunohistochemical staining was used to evaluate the fibrosis degree of tissue. Results  Carnosol could inhibit the proliferation of HSFs in a dose-dependent manner. 30 µmol/L carnosol treatment could significantly inhibit the migration of HSFs. And carnosol could inhibit the collagen secretion and activation of HSFs in a dose-dependent manner. The rabbit ear scar model showed that carnosol could significantly inhibit the formation of hypertrophic scar， manifested as decreased fibrosis degree and decreased expression of α -SMA. Conclusion  Experiments have confirmed that carnosol can significantly inhibit the formation of hypertrophic scar both in vivo and in vitro， and its potential mechanism may be related to the effect of carnosol on fibroblast function.

Key words: Carnosol, &emsp, Fibroblasts, &emsp, Hypertrophic scar