Burn Ointment Promoted Cutaneous Wound for Burns and Scalds by Modulating the PI3K/AKT/mTOR Signaling Pathway

Abstract Background: Burn injury is common, burn ointment (BO) is a common preparation used to treat burns and scalds in folk as an effective remedy for burn healing. The present study was undertaken to evaluate the healing effect and related underlying mechanisms of BO in a model of deep second-degree thermal burn by animal experiments. Methods: BO is was made up of a combination of extracts from several traditional Chinese medicine and borneol, solid paraffin, rapeseed oil, and and its quality control was assessed. The acute toxicity test and skin irritation test were evaluated by rats. The anti-inflammatory effect was revealed by using inflammation animal models, including the xylene-induced auricle swelling in mice and carrageenan-induced toe swelling in rats. The hot plate test was used to evaluate its analgesic activity. Moreover, the experiments of knife and a deep second-degree burn wound were used to explore the effect of BO in promoting wound healing. On days 7, 14 and 28, the wounds were digitally photographed by a camera and after sacrifice of the SD rats, skin samples were obtained for performing H&E staining, immunohistochemical staining and Western Blotting examination. In addition, The expressed of TNF-α, TGF-β1 and VEGF in serum were detected by ELISA kits. Results: BO had no toxicity or side effects on the skin and liver or kidney function. BO could significantly inhibit auricular swelling in mice, paw welling in rats and markedly prolonged the latencies of licking paws in mice; it also could accelerate the process of wound healing and repair scar by promoting the formation of new epithelial tissue. In addition, BO significantly reduced the content of TNF-α and markedly increased the content of VEGF and TGF-β1 in the serum. Moreover, BO promoted the expression of collagen I. Furthermore, it increased the ratio of p-PI3K/PI3K, p-AKT/AKT and p-mTOR/mTOR in the PI3K / AKT / mTOR pathway.Conclusions: BO could effectively reduce inflammation and pain, and effectively accelerate the healing process of deep second-degree burn wounds. And the mechanism of BO promoting wound healing may be related to activate PI3K / AKT / mTOR pathway. therefore, it may be recommended as a promising topical medication for treating burn wounds in the future clinical trials.