Inducing and monitoring photothrombotic stroke in anesthetic neuroprotection-free mice using functional photoacoustic microscopy

Significance: Preclinical ischemic stroke models frequently rely on inhalational anesthetics, which can alter cerebrovascular dynamics and confound ischemic outcomes. The specific impact of anesthesia at the microvascular level remains poorly defined, limiting the translational relevance of preclinical findings. Aim: We aim to utilize an optical resolution photoacoustic microscopy (OR-PAM) system for targeted photothrombosis (PT) induction and functional imaging and compare ischemic responses between awake and anesthetized mice to avoid anesthesia-induced confounding effects. Approach: ), oxygen extraction fraction (OEF), and vascular morphology [arteriovenous diameter, total vessel length (TVL), branch index (BI), vessel area density (VAD)] between awake and anesthetized mice. Behavioral tests and pathological examination were conducted to validate cerebrovascular outcomes. Results: reduction, greater chronic vascular structure degeneration, and more delayed recovery among TVL, BI, and VAD, compared with anesthetized mice. These cerebrovascular outcomes of photothrombotic stroke in anesthetic neuroprotection-free awake mice were further validated by behavioral tests and pathological examination. Conclusions: Our findings address the critical gap of microvascular-level analysis in anesthesia-confounded stroke models. The proposed approach provides a reliable and reproducible tool for the precise induction of cerebral ischemia and dynamic monitoring of vascular changes.