OCLN and Cerebral ischemia: Studies have reported that the expression of VEGFA and its receptors was significantly upregulated in ischemic cerebrovascular disease, which leads to BBB dysfunction by inducing tight junction protein decomposition, occludin transportation, and phosphorylation of occludin protein Ser490, thereby increasing the permeability of the BBB after cerebral ischemia and aggravating cerebral edema [68].