CLDN1 and Hyperglycemia: Cells with SOD2 overexpression under hyperglycemia (HG(4d) + LG(4d)/↑SOD2) did not show suppressed mRNA levels of ZO1 and CLDN1, while knockdown of SOD2 under LG (LG(4d) + LG(4d)/shSOD2) mimicked the HG effect.