Notoginsenoside R1 Facilitates Cell Angiogenesis by Inactivating the Notch Signaling During Wound Healing

The development of chronic, nonhealing wounds is a persistent medical problem that drives patient morbidity and increases healthcare costs. Angiogenesis is a critical accompanying activity in the proliferation stage during the wound healing process. Notoginsenoside R1 (NGR1) isolated from Radix notoginseng has been reported to alleviate diabetic ulcers by promoting angiogenesis and decreasing inflammatory responses and apoptosis. In the present study, we investigated the effect of NGR1 on angiogenesis and its therapeutic functions in cutaneous wound healing. For in vitro evaluation, cell counting kit-8 assays, migration assays, Matrigel-based angiogenic assays, and western blotting were conducted. The experimental results showed that NGR1 (10-50 μM) had no cytotoxicity to human skin fibroblasts (HSFs) and human microvascular endothelial cells (HMEC), and NGR1 treatment facilitated the migration of HSFs and enhanced angiogenesis in HMECs. Mechanistically, NGR1 treatment inhibited the activation of Notch signaling in HMECs. For in vivo analysis, hematoxylin-eosin staining, immunostaining, and Masson's trichrome staining were performed, and we found that NGR1 treatment promoted angiogenesis, reduced wound widths, and facilitated wound healing. Furthermore, HMECs were treated with N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT; a Notch inhibitor), and DAPT treatment was found to exert pro-angiogenic effects. Simultaneously, DAPT was administrated into experimental cutaneous wound healing model, and we found that DAPT administration prevented the development of cutaneous wounds. Collectively, NGR1 promotes angiogenesis and wound repair via activation of the Notch pathway and exhibits therapeutic effects on cutaneous wound healing.