Placental Mesenchymal Stem Cells Promote the Polarization of Astrocytes Towards the A2 Phenotype by Modulating the TGF-β1 Signaling Pathway in Cerebral Ischemia–Reperfusion Rats

Astrocytic function imbalance is a key factor affecting cerebral ischemia rehabilitation. Mesenchymal stem cells have therapeutic potential for cerebral ischemia, but their mechanisms remain unclear. This study explored how placental mesenchymal stem cells pro-mote astrocytes towards the A2 phenotype, which benefits the repair of cerebral ischemia injury. We established the animal model of middle cerebral artery ischemia/reperfusion and an in vitro interleukin-1β-treated astrocyte inflammation model and utilized neuro-logical function assessment, 2,3,5-triphenyltetrazolium chloride staining, immunofluorescence staining, Western blotting and other methods to evaluate the impact and associated mechanisms of transplanting placental mesenchymal stem cells into rats with cerebral ischemia–reperfusion injuries. The results demonstrated that transplantation of placental mesenchymal stem cells ameliorated neurological dysfunction and histopathological damage, alleviated neuroinflammation and enhanced neurotrophic factor levels, promoted the polarization of interleukin-1β-treated astrocytes toward the A2 phenotype, and suppressed the abundance of core mediators within the cerebral TGF β1/Smad signaling cascade in ischemia/reperfusion model. Collectively, placental mesenchymal stem cell grafting facilitates the polarization of cerebral astrocytes toward the protective A2 phenotype, presumably by regulating the TGF β1/Smad signaling cascade in ischemic brain injury.