Inhibitory effects of essential oil from rhizomes of Ligusticum chuanxiong on hypertrophic scarring in the rabbit ear model

Context: Hypertrophic scarring, a common proliferative disorder of dermal fibroblasts, results from an overproduction of collagen and excessive deposition of extracellular matrix. Although the treatment with surgical excisions or steroid hormones can modify the symptoms, numerous treatment-related complications have also been established. Objective: To investigate the effects of essential oil (EO) from rhizomes of Ligusticum chuanxiong Hort. (Umbelliferae) on hypertrophic scarring in a rabbit ear model. Materials and methods: A rabbit ear model of hypertrophic scarring was established. EO (5, 10, and 20%) was applied once daily to the scars for 22 days. After 28 days of post-wounding, excision of scars was respectively performed for both histological examination and assays of the levels of collagen I, collagen III, matrix metalloproteinase-1 (MMP-1), and transforming growth factor beta 1 (TGF-beta beta(1)). The scar elevation index (SEI) was also determined. Results: After 22 days of treatment with indicated concentrations of EO, hypertrophic scarring was significantly inhibited in the rabbit ears. The levels of TGF-beta beta(1), collagen I, and collagen III evidently decreased and MMP-1 level markedly increased in the scar tissue. SEI was also significantly reduced. Immunohistochemical findings exhibited significant amelioration of the scar tissue. Discussion and conclusion: EO suppresses hypertrophic scarring in the rabbit ear model and is a probably effective cure for human hypertrophic scarring.