TLR4 and Cerebral ischemia: These results indicate that IRF3 plays an important role in the protective effect of TLR4 activation by LPS preconditioning against cerebral ischemia, and LPS preconditioning alters the TLR signaling pathway after stroke and has a protective effect against cerebral ischemia mainly through the TRIF/IRF3 signaling pathway (Figure 1B).