Unraveling the complex pathophysiology of white matter hemorrhage in intracerebral stroke: A single‐cell RNA sequencing approach

Abstract Aim This study aims to elucidate the cellular dynamics and pathophysiology of white matter hemorrhage (WMH) in intracerebral hemorrhage (ICH). Methods Using varying doses of collagenase IV, a consistent rat ICH model characterized by pronounced WMH was established. Verification was achieved through behavioral assays, hematoma volume, and histological evaluations. Single‐cell suspensions from the hemorrhaged region of the ipsilateral striatum on day three post‐ICH were profiled using single‐cell RNA sequencing (scRNA‐seq). Gene Ontology (GO) and gene set variation analysis (GSVA) further interpreted the differentially expressed genes (DEGs). Results Following WMH induction, there was a notable increase in the percentage of myeloid cells and oligodendrocyte precursor cells (OPCs), alongside a reduction in the percentage of neurons, microglia, and oligodendrocytes (OLGs). Post‐ICH WMH showed homeostatic microglia transitioning into pro‐, anti‐inflammatory, and proliferative states, influencing lipid metabolic pathways. Myeloid cells amplified chemokine expression, linked with ferroptosis pathways. Macrophages exhibited M1 and M2 phenotypes, and post‐WMH, macrophages displayed a predominance of M2 phenotypes, characterized by their anti‐inflammatory properties. A surge in OPC proliferation aligned with enhanced ribosomal signaling, suggesting potential reparative responses post‐WMH. Conclusion The study offers valuable insights into WMH's complex pathophysiology following ICH, highlighting the significance and utility of scRNA‐seq in understanding the cellular dynamics and contributing to future cerebrovascular research.