Notoginseng leaf triterpenes promotes angiogenesis by activating the Nrf2 pathway and AMPK/SIRT1-mediated PGC-1/ERα axis in ischemic stroke

Notoginseng leaf triterpenes (PNGL), derived from the dried stems and leaves of P. notoginseng, is a phytoestrogen that exerts many neuroprotective effects in vivo and in vitro of ischemic stroke. However, its impact on neurological restoration specifically in relation to angiogenesis following ischemic stroke remains unexplored. The aim of this study was to assess the effects of PNGL on angiogenesis subsequent to ischemic stroke. Male Sprague-Dawley rats were utilized in this study and were subjected to middle cerebral artery occlusion/reperfusion (MCAO/R). Post-ischemia, PNGL were administered through intraperitoneal (i.p.) injection. The highperformance liquid chromatography (HPLC) fingerprinting, triphenyltetrazolium chloride (TTC) staining, immunofluorescent staining, network pharmacology and western blot analyses were assessed to determine the therapeutical effect and molecular mechanisms of PNGL on cerebral ischemia/reperfusion injury. Our findings demonstrate that PNGL effectively reduced infarct volume, enhanced cerebral blood flow, and induced angiogenesis in rats subjected to MCAO/R. Notably, PNGL also facilitated neuronal proliferation and migration in HUMECs in vitro. The proangiogenic effects of PNGL were found to be linked to the activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway and the AMPK/SIRT1-mediated PGC-1/ER alpha axis, as well as the activation of neurological function. Our study provides evidence that PNGL hold promise as an active ingredient of inducing proangiogenic effects, potentially through the activation of the Nrf2 pathway and the AMPK/SIRT1mediated PGC-1/ER alpha axis. These findings contribute to the understanding of novel mechanisms involved in the restoration of neurological function following PNGL treatment for ischemic stroke.