ETHNOPHARMACOLOGICAL RELEVANCE: Huangqi Guizhi Wuwu Decoction (HGWD) is a classic formula recorded in the Jin Gui Yao Lue. It is primarily used to treat symptoms of "blood stasis", such as numbness in the limbs and poor circulation, and has been widely applied clinically in the treatment of stroke. Its traditional efficacy suggests potential for promoting neurological function recovery and regulating the microenvironment. However, its mechanism in neuroprotection and functional recovery after ischemic stroke (IS) remains unclear.
AIM OF THE STUDY: This study aims to elucidate the molecular mechanism by which HGWD exerts neuroprotective effects and promotes neurological recovery following IS by inducing M2 polarization of microglia through activation of the PI3K/Akt/mTOR signaling pathway.
MATERIAL AND METHODS: The chemical constituents of HGWD were identified using Ultra Performance Liquid Chromatography-Mass Spectrometry (UHPLC-MS). Network pharmacology was employed to predict the active components of HGWD and targets, along with potential signaling pathways. A middle cerebral artery occlusion (MCAO) in vivo model was established using Sprague-Dawley (SD) rats, whilst primary microglia were isolated to construct an oxygen-glucose deprivation/reoxygenation (OGD/R) in vitro model. TTC staining was used to assess the volume of cerebral infarction, and neurological function was evaluated using mNSS and the rotarod test. RT-qPCR, Western blot, immunofluorescence, or flow cytometry were used to detect axonal remodeling, the PI3K/Akt/mTOR signaling pathway, and microglial polarization markers, while ELISA was used to detect inflammatory cytokines. The in vivo dosage of HGWD was 2.5 g/kg i.g. and 5 g/kg i.g., and the in vitro concentrations were 50 μg/mL and 100 μg/mL. Using LY294002 and Rapamycin as PI3K and mTOR inhibitors, we verified that HGWD promotes the recovery of neurological function after IS by activating the PI3K/Akt/mTOR signaling pathway.
RESULTS: Network pharmacology revealed that the core components of HGWD overlap with the PI3K/Akt/mTOR signaling pathway and microglial polarization targets. HGWD significantly improved neurological function in MCAO rats, reduced cerebral infarction area, and increased neuronal survival. This formula increased the expression of GAP-43, PSD95, and BDNF, while promoting axonal remodeling and synaptic repair. HGWD inhibited the expression of M1-type markers (CD86, iNOS) and increased the expression of M2-type markers (CD206, ARG1), while ELISA showed a shift of inflammatory cytokines towards anti-inflammatory effects. In microglia, HGWD restored OGD/R-induced cell viability and promoted M2 polarization via the PI3K/Akt/mTOR signaling pathway. Both in vivo and in vitro experiments showed that HGWD significantly increased the phosphorylation levels of PI3K, Akt, and mTOR. LY294002 and rapamycin partially blocked these results, while rescue experiments using the Akt activator SC79 combined with analysis of downstream STAT3 and P65 further illustrate that this process is Akt pathway dependent. The results suggest that HGWD can exert a neuroprotective effect by activating the PI3K/Akt/mTOR signaling pathway, thereby promoting neurological function recovery.
CONCLUSION: HGWD may activate the PI3K/Akt/mTOR signaling pathway, drive microglia to M2 polarization, regulate neuroinflammation, and promote neuroplasticity, thereby achieving neuroprotection and functional recovery after IS.
