The Effect of Qingre Huayu Recipe on Wound Healing after Anal Fistulotomy in Sprague-Dawley Rats

Anal fistula is a common anorectal disease. At present, most scholars believe that its pathogenesis is related to anal gland infection. Anal fistula cannot heal on its own after the onset and must be treated surgically. The wound of anal fistula surgery is open and polluted, and it belongs to three types of three-stage healing; it is the most difficult to heal among all surgical incisions, with a long course of disease, a lot of exudation, and pain for the patient; traditional Chinese medicine has rich experience in the treatment of postoperative wound healing of anal fistula. The study aimed to evaluate the mechanism of Qingre Huayu (QRHY) Recipe on wound healing after fistulotomy on SD rats. SD rats (n = 72) were randomized into three groups post-anorectal surgery. The rats in the positive control group were given potassium permanganate (PP), treatment group were given QRHY, and trauma model group were given 0.9% normal salinity. The changes in wound secretion, granulated tissue, and epithelium tissue were observed, and wound healing rates were evaluated by the discrepancies in wound area. HE and Masson's staining as well as transmission electron microscopy were also performed. The localization as well as the measurement of Ang1, Src, and VE cadherin expression in each group adopted real-time PCR, western blot, and immunohistochemistry (IHC) assays. Statistically higher wound healing rates were observed in QRHY group on days 3, 7, and 14 compared with other groups. Histological analyses showed highly significant increase in collagen and fibroblasts, less inflammatory cells, and vascular endothelial permeability in QRHY rats. The transmission electron microscopy revealed that the intact structure of tight junctions in endothelial cells and well-organized collagen and VE-cadherin, Ang1, and Tie-2 were upregulated by QRHY, while Src was inhibited. This study showed that QRHY can promote wound healing after anal fistulas.