Neuroprotective efficacy of methylene blue in ischemic stroke: an MRI study
Qiang Shen1, Fang Du, Shiliang Huang
1Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America ; Department of Ophthalmology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America ; Department of Radiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America.
Abstract:
Methylene blue (MB) has unique energy-enhancing and antioxidant properties and is FDA-approved drug to treat methemoglobinemia and cyanide poisoning. This study evaluated the efficacy of MB to treat ischemic stroke in rats using longitudinal MRI and behavioral measures. Rats were subjected to 60-minute middle-cerebral-artery occlusion. In a randomized double-blinded design, vehicle or MB was administered after reperfusion. The initial lesion volumes at 30 minutes post-ischemia were not significantly different between the two groups (P = 0.92). The final infarct volumes two days after stroke increased in the vehicle group but decreased in the MB group, yielding a 30% difference in infarct volume (P = 0.03). Tracking tissue fate on a pixel-by-pixel basis showed that MB salvaged more initial core pixels compared to controls (22±3% versus 11±3%, P = 0.03), and more mismatch pixels compared to controls (83±3% versus 61±8%, P = 0.02). This study demonstrates MB treatment minimizes ischemic brain injury and improves functional outcomes.
Insights
Methylene blue (MB) treatment significantly reduced infarct volume and brain injury in rats after ischemic stroke. This FDA-approved drug shows promise for minimizing damage and improving outcomes in stroke patients.
Area of Science:
- Neuroscience
- Pharmacology
- Biomedical Engineering
Background:
- Methylene blue (MB) is an FDA-approved drug with known energy-enhancing and antioxidant properties.
- MB is currently used to treat methemoglobinemia and cyanide poisoning.
- Ischemic stroke remains a leading cause of disability and mortality worldwide.
Purpose of the Study:
- To evaluate the efficacy of Methylene blue (MB) in treating ischemic stroke.
- To assess the impact of MB on infarct volume and brain tissue salvage in a rat model.
Main Methods:
- Rats underwent a 60-minute middle cerebral artery occlusion to induce ischemic stroke.
- A randomized, double-blinded study design was employed, with vehicle or MB administered post-reperfusion.
- Longitudinal magnetic resonance imaging (MRI) and behavioral measures were used to track outcomes.
Main Results:
- No significant difference in initial lesion volume was observed between MB and vehicle groups at 30 minutes post-ischemia.
- MB treatment resulted in a 30% reduction in final infarct volume compared to the vehicle group after two days (P=0.03).
- MB salvaged significantly more initial core pixels (22% vs. 11%, P=0.03) and mismatch pixels (83% vs. 61%, P=0.02) compared to controls.
Conclusions:
- Methylene blue (MB) treatment effectively minimizes ischemic brain injury in a rat model.
- MB administration post-reperfusion leads to reduced infarct volumes and improved tissue salvage.
- These findings suggest MB holds therapeutic potential for treating ischemic stroke.
