TLR9 and brain ischemia: Importantly, one study showed that the drug preconditioning of the TLR9 ligand CpG-ODNs could also produce a protective effect in a model of cerebral ischemic injury in the non-human primate rhesus monkey, and the reagents applied in this experiment have been used in human clinical trials, which provides a new preventive approach for patients at high risk of cerebral ischemia [96].