TNF and brain edema: Some scholars believe that TNF-α is directly related to BBB damage in cerebral ischemia/reperfusion injury and that TNF-α can directly activate white blood cells, increase the adhesion between white blood cells and endothelial cells, resulting in vascular hypoperfusion, and thus penetrate into the brain through the tight connection between endothelial cells and through the BBB to form cerebral edema.