TNF and brain infarction: In the early ischemic phase of cerebral infarction, microglia are activated and their released inflammatory mediators, such as interleukin (IL) class and tumor necrosis factor-α (TNF-α), induce vascular endothelial cells to express adhesion molecules, etc., prompting circulating leukocytes (neutrophils, monocytes-macrophages, and lymphocytes) to roll and adhere to the injured vascular endothelium, migrate and cross the blood-brain barrier, and infiltrate and infiltrate the brain parenchyma.