Zinc Deficiency Exacerbates Loss in Blood‐Brain Barrier Integrity Induced by Hyperoxia Measured by Dynamic MRI

Abstract. Using dynamic Magnetic Resonance Imaging (dMRI), blood‐brain barrier (BBB) permeability ( k PSρ ) and tissue interstitial leakage space ( v e ) were evaluated in zinc‐deficient (ZnDF) male weanling Wistar rats following 3 days exposure to hyperoxia (85% O 2 ). Temporal monitoring of T1‐weighted MR image changes, following a bolus intravenous injection of gadolinium‐DTPA, allowed estimation of BBB integrity. Three‐day exposure of hyperoxia caused a marginal loss of BBB integrity, reflected in a slight increase in k PSρ and v e , observed in both the animals fed adequate zinc (ZnAL) and pair‐fed controls (ZnPF). However, zinc deficiency resulted in a significant increase in both k PSρ and v e , indicating a severely disturbed BBB. In addition MR‐visible free water was elevated in ZnDF brains following hyperoxia treatment indicating that a loss of BBB integrity may be associated with neuronal edema. The diminished BBB integrity may be free‐radical mediated as the ratio of oxidized to reduced glutathione (GSSG:GSH) was significantly elevated.