Effect of the Ruan Jian Qing Mai Recipe on Wound Healing in Diabetic Mice and Prediction of its Potential Targets

Background: The “Ruan Jian Qing Mai (RJQM) recipe” is a traditional Chinese medicine (TCM), which has been found to have significant curative effects on diabetic ulcers in the clinic for a long time. Previous research has shown that RJQM can improve diabetic skin wound healing and promote angiogenesis. However, the active ingredients of the RJQM recipe and its pharmacological mechanism of treatment for diabetic skin wound healing still remain unclear.This study aims to investigate the effect of the RJQM recipe on diabetic wound healing, and to identify the possible active ingredients and their mechanism. Methods: First, a skin injury model was established in diabetic mice, and wound healing was evaluated by hematoxylin-eosin (HE) staining, quantitative reverse transcription-polymerase chain reaction (RT-qPCR), and western blot analysis. Second, the chemical constituents of the RJQM recipe were analyzed and identified by ultra pressure liquid chromatography-mass spectrometry (UPLC-MS). Finally, the possible targets of drug treatment for diabetic skin injury were analyzed by network pharmacology and verified by in vitro experiments using cell culture. Results: (1) In the full-thickness skin injury model, the skin wound healing rate and healing area were significantly increased in mice treated with the RJQM recipe compared with those of the model group. The results of immunofluorescence staining showed that the RJQM recipe could increase the expression of VEGF protein and promote the proliferation of vascular smooth muscle cells and the formation of microvessels, and RT-qPCR results found that the mRNA expression of angiogenesis-related factors in the RJQM recipe group was significantly higher than that in the model group. (2) A total of 25 compounds were identified by UPLC-MS. (3) According to the results of network pharmacology, the therapeutic effect of the RJQM recipe on diabetic skin injury may be related to S6 (quercetin), S1 (typhaneoside), S18 (isoliquiritigenin), protein kinase B-α (Akt1), phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1), insulin-like growth factor I receptor (IGF1R), vascular endothelial growth factor-a (VEGF-a), signal transducer and activator of transcription-3 (STAT3) and phosphoinositide 3-kinase-protein kinase B (PI3K-Akt) signaling pathways. Based on the predictions by network pharmacology, we proved that the drug could treat diabetic skin damage by activating the PI3K-Akt-VEGF signaling pathway. Conclusion: The RJQM recipe promotes the formation of granulation tissue during the process of wound healing and exerts a good therapeutic effect on diabetic skin wound healing.