The effect of methylene blue on white matter injury after MCAO in rats and mice

Objectives: Methylene blue, the FDA-grandfathered drug was proved to be
neuroprotective in ischemic stroke in rat. However, the mechanism of the
protective effect was unknown. In this study, we used different animal
models to investigate the effect of MB administration given within and
beyond the therapeutic time window on behavioral deficits and infarct
volume and related mechanism about the white matter protection. Methods:
Middle cerebral artery occlusion and reperfusion (MCAO) and
photothrombotic middle cerebral artery occlusion (PT-MCAO) models were
used. Behavioral deficits and infarct volume were measured by foot fault
test, Garcia neurological score and TTC staining. Black gold staining and
western blot were used to evaluate the brain white matter injury. Results:
We found that intraperitoneal administration of MB immediately or 24h
after the MCAO or PT-MCAO surgery reduced infarct volume, improved the
neurological deficits, reduced the white matter injury via myelin Basic
Protein (BMP) protection. Conclusion: These findings suggested that MB
relieved white matter injury besides neuronal protection and has potential
therapeutic effects on ischemic stroke.