Effects Of Adenosine Preconditioning On The Levels Of IL-1β,IL-6 And COX-2 In The Brain Of Rats With Cerebral Ischemia Reperfusion Injury

Background With the increasing popularization of stroke-related medical knowledge among the population and the development of modern medical service system,more and more patients with ischemic stroke get blood flow reconstruction in ischemic area in acute stage.However,the prognosis of patients with ischemic stroke is not matched with a high recanalization rate.The inflammatory reaction in the brain after cerebral ischemia reperfusion is the core factor affecting the prognosis of patients.It has been found that adenosine preconditioning can play a neuroprotective role in cerebral ischemia-reperfusion injury,but its mechanism remains to be further explored.Purpose To study the changes of inflammatory factors IL-1β,IL-6 and inflammatory mediators COX-2 in the brain of rats after cerebral ischemia-reperfusion and to explore the effect of adenosine preconditioning on them.Methods Eighty-five Sprague-Dawley rats were randomly divided into four groups: control group(n= 10),sham operation group(n=25),model group(n=25)and adenosine group(n=25).The rats in the adenosine group were pretreated by intraperitoneal injection of 2ml normal saline dissolved with 0.15mg/100 g adenosine for pretreatment 3 days before modeling.The sham operation group and the model group were injected with 2ml saline at the same time and in the same way as the adenosine group before operation.The right middle cerebral artery ischemia-reperfusion operation was performed in the adenosine group and the model group.The thread bolt was not inserted in the sham operation group during the operation.The remaining operations were the same as that in the model group,and the control group did not receive any treatment.The contents of IL-1β and IL-6 in the brain of rats were detected by ELISA(double antibody sandwich enzyme-linked immunosorbent assay)at 6h,12 h,24h and 48 h after sham operation or reperfusion,and the number of COX-2 positive cells in the brain of rats in each group was detected by IHC(immunohistochemistry)to investigate the effect of adenosine preconditioning on the inflammatory reaction in the brain of rats with cerebral ischemia-reperfusion model.The neuroprotective effects of adenosine preconditioning on cerebral ischemia-reperfusion rats were investigated by neurological deficit score,TTC(2,3,5-triphenyltetrazolium chloride)staining and TUNEL(terminaldeoxynucleotidyl transferase mediated nick end labeling)24 hours after sham operation or reperfusion.Results 1.Neurological deficit score,proportion of cerebral infarction volume and brain apoptosis index: There was no cerebral infarction or neurological dysfunction in the control group and sham operation group,and a small number of apoptotic cells were found in the brain of the two groups,but there was no significant difference in apoptosis index between the two groups(P＞0.05).The apoptosis index of brain cells in model group and adenosine group was significantly higher than that in sham operation group(P＜0.01).The nerve defect score,the proportion of cerebral infarction volume and the apoptosis index of brain cells in the adenosine group were significantly lower than those in the model group(P＜0.05).2.The levels of IL-1β and IL-6 in brain: At 12 h and 24 h after operation,the levels of IL-1β in the brain of rats in sham operation group were significantly higher than those of the control group(P＜0.05);At 6h,12 h,24h and 48 h after sham operation or reperfusion,the levels of IL-1β and IL-6 in the brain of rats in the model group and adenosine group were significantly higher than those in the sham operation group(P＜0.01),and the levels of IL-1β and IL-6 in the brain of rats in adenosine group were significantly lower than those in the model group(P＜0.01);The levels of IL-1β and IL-6 in the brain of rats in the model group reached the peak at 24 h after reperfusion.3.The expression index of COX-2 in brain tissue: The expression index of COX-2 in brain of rats in the sham operation group was significantly higher than that of control group at 24 h after operation(P＜0.05);At 6h,12 h,24h and 48 h after sham operation or reperfusion,the expression index of COX-2 index in the brain of rats in the model group and adenosine group was significantly higher than that in the sham operation group(P＜0.01),and the expression index of COX-2 in the brain of rats in adenosine group was significantly lower than that in the model group(P＜0.01);The expression index of COX-2 in the brain of rats in the model group reached the peak 24 hours after reperfusion.Conclusions 1.The levels of IL-1 β,IL-6 and COX-2 in the brain of rats with cerebral ischemiareperfusion injury reached the peak at 24 hours after reperfusion.2.The protective mechanism of adenosine preconditioning on cerebral ischemiareperfusion injury in rats is closely related to the decrease of the levels of IL-1 β,IL-6 and COX-2 in the brain of rats.