Zinc deficiency exacerbates loss in blood-brain barrier integrity induced by hyperoxia measured by dynamic MRI

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