Advantage effect of Dalbergia pinnata on wound healing and scar formation of burns

Dalbergia pinnata, as a natural and ethnic medicine in China, has been used for burns and wounds with a long history, which has the effect of invigorating blood and astringent sores. However, there were no reports on the advantage activity of burns.The purpose of this study was to screen out the best active extract part of Dalbergia pinnata and investigate its therapeutic effect on wound healing and scar resolution.Rat burn model was established and the healing effects of extracts from Dalbergia pinnata on burn wounds were evaluated by the percentage of wound contraction and period of epithelialization. Histological observation, immunohistochemistry, immunofluorescence and ELISA were used for the examination of inflammatory factors, TGF-β1, neovascularization and collagen fibers through the period of epithelialization. In addition, the effect of the optimal extraction site on fibroblast cells was evaluated by cell proliferation and cell migration assays. The extracts of Dalbergia pinnata were analyzed by UPLC-Q/TOF-MS or GC-MS technique.Compared to the model group, there were better wound healing, suppressed inflammatory factors, more neovascularization as well as newly formed collagen in the ethyl acetate extract (EAE) and petroleum ether extract (PEE) treatment groups. The ratio of Collagen I and Collagen III was lower in the EAE and PEE treatment groups, suggesting a potential for reduced scarring. Furthermore, EAE and PEE could repair wounds by up-regulating TGF-β1 in the early stage of wound repair and down-regulating TGF-β1 in the late stage. In vitro studies showed that both EAE and PEE were able to promote NIH/3T3 cells proliferation and migration compared with the control group.In this study, EAE and PEE were found to significantly accelerate wound repair and might have an inhibitory effect on the generation of scars. It was also hypothesized that the mechanism might be related to the regulation of TGF-β1 secretion. This study provided an experimental basis for the development of topical drugs for the treatment of burns with Dalbergia pinnata.