TNF and Stroke: During the early phase of stroke, activated microglia and infiltrated blood-derived macrophages secrete both pro- and anti-inflammatory factors, e.g., IL-1β, IL-6, tumor necrosis factor α (TNF-α), transforming growth factor beta (TGF-β), and activate pro-inflammatory enzymes, such as cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (NOS2/iNOS) [2–4].