Comparison Evans Blue injection routes: Intravenous versus intraperitoneal, for measurement of blood-brain barrier in a mice hemorrhage model

Aims: Intracerebral hemorrhage is one of the most devastating subtypes of stroke, leaving survivors with severe neurological deficits. Disruption of the blood brain barrier (BBB) following hemorrhage results in the development of vasogenic brain edema, a most life-threatening event after such events as intracerebral hemorrhage (ICH). The Evans Blue assay is a popular method for the quantification of BBB disruption. Although this method is in common use, there are several protocols of the assay in the literature which vary in the route of administration, as well as the circulation time of the stain. In this study, we compared the amounts of accumulated stain in brain tissue following intraperitoneal versus intravenous injection at 0.5, 3 and 24h of circulation time.

Methods: 58 CD-1 mice were used. Animals were divided into ICH (N=42), sham groups (N=6) and naïve (N=10). ICH Animals received stereotactic injection of collagenase type VII into the right basal ganglia. Sham Animals received only needle trauma. Evans Blue stain was injected 24h after collagenase injection or needle trauma. The consistency of ICH produced was characterized by estimation of hematoma volume via hemoglobin assay and neurological evaluation.

Results: The produced hematoma and neurological deficits were well comparable between different experimental groups. There was no statistically significant difference in the results of the Evans Blue assay with regard to administration route.

Conclusions: The amount of Evans Blue stain accumulated in the brains of mice after ICH produced by collagenase injection was independent of the stain administration route.