Introduction

Ischemic stroke represents as a major contributor to global burden of death and long-term disability, representing approximately 80% of all stroke cases1–3. The reperfusion strategies, including intravenous thrombolysis and mechanical thrombectomy, have improved patients’ quality of life, but their overall clinical benefit is still constrained by narrow therapeutic windows, restricted availability of specialized care, and procedure-related complications4,5. Consequently, a substantial proportion of patients continue to experience lasting neurological deficits, underscoring the need to develop novel therapeutic strategies to enhance functional recovery.

Chemokines are regulators of post-ischemic neuroinflammation, mediating the recruitment of peripheral immune cells into the central nervous system6,7. Among them, CXCL16 has attracted increasing attention due to its involvement in neuroinflammatory regulation and its interaction with microglia4,8–10. Microglia exhibit marked temporal and functional heterogeneity following ischemic stroke and adopt a continuum of context-dependent states rather than discrete M1/M2 phenotypes. These states are characterized by overlapping inflammatory, homeostatic, phagocytic, and repair-associated programs that evolve across different stages of injury and recovery. However, the role of CXCL16 in shaping microglial functional states after ischemic injury remains poorly understood.

Apoptosis dominates post-ischemic cell death11,12. Unlike necrotic cell death, apoptosis is a highly regulated process in the ischemic penumbra, making it an attractive therapeutic target for limiting secondary brain injury after stroke13,14. Given that CXCL16 has been shown to exert neuroprotective effects under pathological conditions15, it is of interest to investigate whether CXCL16 may attenuate apoptotic cell death in the context of ischemic injury.

These observations prompted us to determine the involvement of CXCL16 on microglial functional states under cerebral ischemic conditions and to explore its potential role in modulating apoptotic cell death.