FIGURE 4.

BBB integrity is impaired in apoE4-knock-in mice. The BBB integrity in apoE3-knock-in mice, apoE4-knock-in mice, and apoE-KO mice was evaluated using an Evans blue dye technique. Two hundred microliters of 20% mannitol was injected through the tail vein. Thirty minutes after injection, 200 μl of 2% Evans blue dye was injected intraperitoneally. The distribution of the dye was confirmed by a visible change in the color of the skin within 1 h after injection. Three hours after the injection, the mice were killed, and their brains were removed. The cerebrum and cerebellum were immediately collected, weighed, and incubated in 500 μl of formamide for 72 h at room temperature in the dark. The absorbance of the extracted dye was measured at 630 nm. The data presented are means ± S.D. (error bars) (n = 3). *, p < 0.05.