A: BRB breakdown is detected by Evans blue dye leakage assay (n=6); B: Retinal mRNA expression of occludin, ZO-1, claudin-1, claudin-5 and claudin-19 (n=3-5); C: Retinal protein expression of claudin-1 and claudin-19, representative blots for claudin-1, claudin-19 and actin, and the results represent at least three independent experiments; D: The quantitative densitometric analysis of claudin-1 and claudin-19, and the results are presented as percentage of control (n=4-5). aP<0.05, bP<0.01, eP<0.001 compared to control; cP<0.05, dP<0.01, fP<0.001 compared to DM.