Abstract TMP20: The Therapeutic Gas Carbon Monoxide (CO) Attenuates Vasospasm and Improve Neurobehavioral Function After SAH
Introduction: Subarachnoid hemorrhage (SAH) is one of the most devastating forms of hemorrhagic stroke and it is a serious medical condition caused by bleeding of a ruptured aneurysm. The etiopathology of the disease includes early brain injury, vasospasm, and delayed cerebral ischemia. Blood byproducts cause the walls of arteries to constrict and spasm. At physiological concentrations, we and others have reported that carbon monoxide (CO) has functional roles in neuroprotection through anti-inflammation, anti-oxidative stress, and improving blood flow. Hence, this study focuses on the safe noninvasive therapeutic strategy to treat SAH by using CO as therapeutic medical gas. Hypothesis: We propose that CO may prevent SAH by mitigating vasospasm, limiting brain injury and improving functional outcomes. Methods: SAH was induced in adult mice using the endovascular perforation method. Mice were treated either with 250ppm CO or medical Air (at the same flow rate) after 2h of SAH for 1h daily for 7d. Such CO administration protocol keeps carboxyhemoglobin within normal range. Neurobehavioral outcomes such as focal neurological deficit score, open field activity, and motor functions were monitored at day 1 and day 7. Data acquisition and statistical analysis were performed by an investigator blinded to the intervention. Results: At 7d after SAH, CO decreased neurological deficit score (47.4±10.5%, p<0.05), and increased activity (30.0±9.1%, p<0.05) and stereotypic counts (261.5±62.1%, p<0.01) as compared to the air control group. No significant changes in motor function were observed in CO treated mice as compared to SAH at either day 1 or day 7). Of interest, there was a significant increase in CO treated group’s lumen area/wall thickness ratio in the middle cerebral artery (173.5±19.3%, p<0.01) and trended to increase in the anterior cerebral artery (25.5±4.3%, p=0.58) at 7d. Conclusion: This is a first report to demonstrate that CO prevents delayed SAH-induced neurobehavioral deficits, which suggest that post-treatment with CO should be considered a therapeutic strategy against SAH.