Evaluation of the wound healing potential of Sophora alopecuroides in SD rat's skin

Sophora alopecuroides Linn. (Leguminosae) has been largely used in traditional folk medicine in China as an anti-inflammatory agent and to treat various skin wounds, including sore furunculosis and ulcer (a common type of non-healing wound). The present study aimed to evaluate the effects of S. alopecuroides gel on skin wound healing in rats. When the rats were anesthetized, full-thickness skin wound was performed on dorsal area by using biopsy punch with 8 mm diameter. Then, wounds received treatment with different doses of S. alopecuroides gel (1.25%, 2.5% and 5%, w/w) once a day with the gel base used as vehicle control and rb-FGF as positive control. Every five animals were sacrificed after 7, 12 days after surgery for histopathology and relevant biochemical indexes analysis. Besides, after RAW 264.7 cells exposure to LPS (1 μg/ml) with or without total extract (25 and 50 μg/ml) for 24 h, the culture supernatant was used for detection of IL-1β and TNF-α levels using ELISA kits and the protein lysate for western blot analysis. A remarkable wound closure was observed after administration with 5% S. alopecuroides gel with the wound area of 30% and 8.5% as compared to 42% and 19% in the control group on day 7 and 12, respectively. Histological and immunostaining analysis for the wound tissues also revealed that S. alopecuroides promoted the growth of granulation tissue, collagen deposition, cell proliferation and angiogenesis. Meanwhile, it was able to ameliorate inflammatory response and promote the production of TGF-β. In addition, we also demonstrated that S. alopecuroides inhibited the release of inflammatory mediators and expression of iNOS as well as up-regulated the expression of Arg-1 in LPS-triggered RAW 264.7 cells. The present study confirmed that S. alopecuroides had a great potential for accelerated wound healing by regulating the over expression of inflammatory response for the first time and provided theoretical basis for the traditional use. It can be used as candidate drug for the treantment of chronic non-healing wounds.