Blood-Brain Barrier Dysfunction After Smoke Inhalation Injury, With and Without Skin Burn

Only a handful of published reports exist today that describe neurological complications following smoke inhalation injury. In this study, we characterize acute pathophysiological changes in the brain of sheep exposed to smoke inhalation, with- and without third-degree skin burn that models the injuries sustained by human victims of fire accidents. Blood-brain barrier integrity and hemorrhage were analyzed throughout the brain using specific histological stains: Hematoxylin & Eosin, Luxol fast blue, Periodic acid-Schiff (PAS), and Martius, Scarlet and Blue (MSB). Our data show that, following smoke inhalation injury, alone and in combination with third-degree skin burn, there was a significant increase in the number of congested and dilated blood vessels in the frontal cortex, basal ganglia, amygdala, hippocampus, pons, cerebellum, and pituitary gland as compared to sham-injured controls. Positive PAS staining confirmed damage to the basement membrane of congested and dilated blood vessels throughout the brain. Severe rupturing of blood vessels, microvascular hemorrhaging and bleeding throughout the brain was also observed in the injured groups. No significant changes in hemodynamics and PaO2 were observed. Our data demonstrate for the first time that acute smoke inhalation alone results in diffuse blood-brain barrier dysfunction and massive bleeding in the brain in the absence of hypoxia and changes in hemodynamics. These findings provide critical information and prompt further mechanistic and interventional studies necessary to develop effective and novel treatments aimed at alleviating CNS dysfunction in patients with smoke and burn injuries.