The Effects Of Minocycline On The Expression Of NF-κB, ⅠκBα And TNF-α In Focal Cerebral Ischemia-Reperfusion Rats

ObjectiveIschemic cerebrovascular disease(ICVD) become one of the most important disease because of its'high morbidity, mortality and disability rate. The treatments of thrombolysis, anti-platelet and anticoagulation have been confirmed to be efficient.Only Thrombolytic, anti-platelet and anticoagulation have been proved to be the efficient treatments for the cerebral ischemia diseases.The revascularization after thrombolytic usually bring reperfusion injury. The cerebral ischemia reperfusion was a very complex pathological prosess. Inflammatory reaction plays a important role in the ischemia reperfusion process. Nuclear factor kappa B (NF-κB) is one of key Inflammatory modulators during the possess and P50 and P65 are the two most important subunits which combined as a dimmer.The phosphorylation degrades the NF-κB inhibitor is the main pathway for NF-κB activation. Activation of NF-κB offers a potential molecule target for the inhibition of complex mechanism of inflammatory and cell apoptosis. Minocycline is a second-generation tetracycline analog which can facilely cross the blood-brain barrier. Its'neuroprotection effects in animal models of ischemic injury was first reported in 1998 by Yrjanheikki, but its mechanism was still unclear. Our experiment observed the effects of Minocycline on the expression of IκBα,NF-κB p65,TNF-αand both the pathology change and neuron apoptosis in cerebral ischemia-reperfusion rats to explore the possible neuroprotective mechanism of Minocycline.Material and methods72 healthy adult S-D rats were randomly divided into the Sham-operated group (Sham), ischemia-reperfusion group (IR) and MC treatment group (MT).The model of Intraluminal Thread Occlusion Model was established according to Zea Longa's method after a advisable improvement. The operation of Sham group was treated just the same as the other two groups besides without the insertion thread. Minocycline was delivered by intragastric administration after reperfusion (first dose was 45mg/kg, others 22.5mg/kg every 12h), and both The Sham group and IR group were delivered physiological saline at the same time point until they were sacrificed.The brain histopathology was observed at 48h after reperfusion by H-E staining. We detected neuron apoptosis by TUNEL to evaluate the ischemia-reperfusion injury and the neuroprotective effect of minocycline. The expression of IκBαNF-κB p65 and TNF-αwere further detected by immunohistochemistry to observe the variation and the effects of minocycline.Results(1) Compared with the IR group, the pathological change of brain tissue was obviously relieved after cerebral ischemia-reperfusion 48h;(2) Compared with the IR group, the neuron apoptosis was significantly decreased in the MT group after cerebral ischemia-reperfusion 48h;(3) The expression of NF-κB p65 positive cells has increased significantly after reperfusion 6h and approach the max on 24h,then it has slightly decrease on 48h.The expression of TNF-a positive cells has increased significantly after reperfusion 6h and approach the max on 24h,then it still keep a high level on 48h.On the according time point, the positive cell numbers of NF-κB p65 or TNF-αin IR group were significantly higher than the Sham group(P<0.01) and the MT group(P< 0.05);(4) Compared with the IR group, the optical density value of IκBαwas lowest at 12h and began to recover at 24h(P<0.05), it increased significantly on the corresponding time pointing in MT group but decreased greatly compared with sham group (P<0.01). Conclusions(1) The expression of IκBαwas decreased but NF-κB p65 was over-expressed in rats after Focal Cerebral Ischemia-Reperfusion.(2) MC can increase The expression of IκcBαbut decease the expression of NF-κB p65 and TNF-α, MC play a neuroprotective role in Focal Cerebral Ischemia-Reperfusion injury rats maybe by partly blocking up the inflammatory process and reducing neuron apoptosis.