Reversible blood-brain barrier dysfunction after intracarotid hyperthermic saline infusion

Abstract

An animal model for reversible blood-brain barrier disruption has been developed. Retrograde infusion of hyperthermic saline solution 43d`C into the left external carotid artery of normothermic, Wistar rats, reversibly increases cere-brovascular permeability to Evans-blue albumin in the left cerebral hemisphere. Isotonic saline solutions at 37d`C for group I and 43d`C for group II were infused for 30-s at a constant rate of 0.12ml/s into the left external carotid artery. Evans-blue, the barrier tracer was administered intravenously either prior to or at intervals of 5, 30, 180, 360 min after the hyperthermic saline infusion under pentobar-bital anesthesia. All animals receiving hyperthermic saline perfusion had disturbed blood-brain barrier permeability. Based on visual inspection, disruption grade in the left hemispheres of six of 11 animals was grade 3 +. Mean values for Evans-blue dye were found to be 0.28 ± 0.06 mg/g of tissue in left hemisphere after normothermic saline infusion (group I), and 2.41 ±0.5 mg/g of tissue in the same hemisphere after hyperthermic saline infusion (group II). The difference was found to be significant between group I and group II (p < 0.01). The increase in cerebrovascular permeability was temporary, even though Evans-blue albumin extravasation remained slightly elevated 3h after infusion and was normal 6h after infusion.

Key Words:

• Hyperthermia
• blood-brain barrier
• Evans-blue
• left hemisphere right hemisphere