Rhynchophylline promotes microglia phenotypic transformation and repair of cerebral ischaemic injury through the JAK2/STAT3 pathway.

Background: Rhynchophylline (RIN) is an alkaloid known for its ability to effectively block signal transduction related to various neurodegenerative diseases. However, the specific mechanism by which RIN regulates microglial activation and cerebral ischemia remains unexplored. This study aims to investigate the function and molecular pathways through which RIN activates the JAK2/STAT3 signaling cascade, promoting the transformation of microglial phenotypes that contribute to recovery from cerebral ischemic injury.

Methods: By establishing a microglia oxygen glucose deprivation/reoxygenation (OGD/R) model and a middle cerebral artery occlusion animal model, we assessed changes in the expression of phenotype-specific marker factors for M1 and M2 microglia, as well as key proteins in the JAK2/STAT3 pathway, utilizing ELISA and Western blot techniques. Histological examination, including HE staining, TUNEL assay, and immunofluorescence, was employed to evaluate pathological changes in brain tissue, along with cell apoptosis and proliferation.

Results: The results indicated that microglial activity was significantly reduced and shifted towards the M1 phenotype following OGD/R. However, RIN treatment reversed these changes. When JAK2/STAT3 inhibitors were combined with RIN, it inhibited RIN's protective effect. Animal studies have shown that RIN reduces histopathological changes associated with cerebral ischemia. Additionally, RIN inhibited microglial proliferation in ischemic cortical tissue and increased the expression of M2-type marker proteins, as well as the levels of phosphorylated JAK2 and STAT3 in the ischemic tissue.

Conclusion: In conclusion, this study indicates that RIN may protect against cerebral ischemic injury by activating the JAK2/STAT3 pathway, which promotes the transition of microglia to the M2 phenotypic.