Inhibition of mechanical stress-induced hypertrophic scar inflammation by emodin

At least 50% of hypertrophic scarring (HS) is characterized by inflammation, for which there is currently no effective treatment available. Emodin is a major component of the widely used Chinese herb, rhubarb, which has been used to treat inflammation in several types of disease. However, few studies have investigated the efficacy of emodin in the treatment of HS. In the present study, a mouse model with mechanical stress-induced HS was used to investigate the effects of emodin (20, 40, 80, or 120 mg/ml on HS, and to determine the potential underlying mechanisms. Treatment with emodin significantly attenuated HS inflammation, as determined by histopathological assessment of the scar elevation index, collagen structure and inflammation (P<0.05). Furthermore, treatment with emodin (40 mg/ml) markedly inhibited phosphoinositide 3-kinase (PI3K)/Akt activity (P<0.01) and this attenuation was associated with reduced expression levels of tumor necrosis factor-alpha, interleukin-6 and monocyte chemoattractant protein-1 (P<0.05) in the HS tissue. The results of the present study indicated that administration of emodin had therapeutic effects on the progression of HS and the underlying mechanism of this may be due to inhibition of the PI3K/Akt signaling pathway.