Increases in brain water content and disruption of BBB after cold injury.

(A): Time-course of increases in brain water content. After cold injury in the left hemisphere of mouse brain, 4-mm sagittal brain sections containing the injured area were made at the times indicated. Water content was calculated by the formula: water content (%)  =  (wet weight−dry weight)×100/wet weight. Results are means ± SEM of six to eight experiments. *p<0.05, **p<0.01 vs. 0 h by one-way ANOVA followed by the Dunnett’s test. (B) Time-courses of extravasation of endogenous albumin: After cold injury, mice were perfused with 50 mL saline, and the injured hemispheres were removed at the times indicated. Endogenous albumin in the cerebrum was measured using an ELISA kit. Results are means ± SEM of six to eight experiments, expressed as albumin content (ng) per weight of cerebral tissue (g). **p<0.01 vs. 0 h by one-way ANOVA followed by the Dunnett’s test. (C) Time-courses of extravasation of Evans blue: After cold injury, Evans blue was injected into the tail vein 90 min before removal of the injured hemisphere. The amount of Evans blue was measured and expressed as percentage of Evans blue in brain (µg/g) to that of serum (µg/mL). Results are means ± SEM of six to nine experiments. **p<0.01 vs. 0 h by one-way ANOVA followed by the Dunnett’s test. Photograph shows a representative example of Evans blue extravasation 12 h after cold injury.