Effects of Ischemic Postconditioning on TLR4 Signaling Pathway During Focal Cerebral Ischemla/Reperfusion in Rats

Objective:To investigate the effect of ischemic postconditioning on TLR4 signaling pathway during focal cerebral ischemic reperfusion in rats.Methods: One hundred and ten adult healthy male Sprague-Dawley rats were randomly divided into sham group(n=10),ischemia/reperfusion group and ischemic postconditioning group.The latter groups was equally divided into five subgroups according to different time points of the ischemia-reperfusion(6,12,24,48,and 72 h)(n=10),The models of focal brain ischemia were established by intraluminal thread middle cerebral artery occlusion(MCAO) methods.For IP,the rats were subjected to 3 cycles of 15-second/15-second reperfusion/reocclusion after 2 h MCAO.Each group was evaluated with examinating neurobehavioral function deficit scores and infarct volume.The apoptotic cells were counted by TUNEL method.The immunohistochemistry stain was used to determine the expressions of TLR4,NF-κ B and tumor necrosis factor-α(TNF-α).The levels of TLR4mRNA and NF-κ BmRNA were examined by In Situ Hybridization(ISH).Results: Ischemic postconditioning could down-regulate the expressions of TLR4,NF-κ B and TNF-α,inhibit apoptosis,reduce the cerebral infarct volumes,and improve the neurobehavioral function of rats.Conclusions: IP could reduce the infarct volumes and improve neurobehavioral function through inhibiting the expressions of TLR4 signaling pathway.