TNF and ischemia: NLRP3, being a member of the pattern recognition receptor family, is directly induced by many external stimuli (such as ischemia), which in turn activates Pro-Caspase-1 into Caspase-1 to bind to IL-1β precursor, resulting in the increase of synthesis and secretion of IL-1β and TNF-α and thus participating in immunoreaction [24].