The Effect Of Artificial Synthetic E-selectin On Expression Of VCAM-1and VCAM-1mRNA After Focal Cerebral Ischemia-reperfusion Injury In Rats

Part I The establishment of modified focal cerebral ischemia-reperfusion injury model in rats and the effect of artificial synthetic E-selectin on cerebral infarction volumeBackgrounds and Objectives:Zea Longa et al used the suture to block the blood flow of anterior cerebral artery,common carotid artery and posterior communicating artery to occluse the middle cerebral artery,then removed the suture to reperfuse the brain tissue to establish focal cerebral ischemia-reperfusion injury model.Now we want to improve Zea Longa’s method to create a model with higher success rate and better stability.We will also study the effect of artificial synthetic E-selectin on cerebral infarction volume.Methods:90male Sprague-Dawley rats were randomly divided into sham operation group,model group,artificial synthetic E-selectin treated group. We used neck paramedian incision,not ligationg of the pterygopalatine artery,inserting the suture from the carotid artery and other approaches to improved Zea Longa’s method to establish the focal cerebral ischemia-reperfusion injury model.The reliability and stability of this model were evaluated by the result of neurological behavior score and TTC staining.We used the relevant software and formulas to calculate the cerebral infarction volume.Results:The neurological behavior score of successful model is1-3points,and the color of ischemic brain tissue is pale after TTC staining.The success rate of the modified model is80%.The cerebral infarction volume of treated group is233±15mm3,less than287±19mm3of model group(P<0.05).Conclusions:The advantages of modified model are simple operation, good stability and high success rate.lt is an ideal experimental animal model to study focal cerebral ischemia-reperfusion injury.The artificial synthetic E-selectin can reduce the cerebral infarction volume and it has brain protective effect. Part Ⅱ The effect of artificial synthetic E-selectin on expression of VCAM-1protein and mRNA after focal cerebral ischemia-reperfusion injury in ratsObjectives:To investigate the effect of artificial synthetic E-selectin on expression of VCAM-1and VCAM-1mRNA after focal cerebral ischemia-reperfusion injury in rats and to explore its mechanism of action.Methods:42male SD rats were randomly divided into sham operation group, model group,artificial synthetic E-selectin treated group.We Used modified Zea Longa’s method to establish cerebral ischemia-reperfusion injury model and injected10mg/Kg artificial synthetic E-selectin into the femoral vein of the rats of treated group.Immunohistochemistry was employed to observe the microvascular positive cell count of VCAM-1in the ischemic brain tissue,RT-PCR method was used to observe the mRNA expression of VCAM-1.Results:1. Sham operation group:The positive cell count of VCAM-1was very small.And the expression of VCAM-1mRNA was low.2.Model group:The VCAM-1-positive cell was found at2h after reperfusion,increased with time goes by, reached peak at24h,and then decreased at72h. The expression of VCAM-1in model group was more than sham operation group at each time point(P<0.01). VCAM-1mRNA was expressed at2h after reperfusion,peaked at12h and decreased at24h. The expression of VCAM-1mRNA in model group was also more than sham operation group at each time point(P<0.01).3.Treated group:The positive cell count of VCAM-1was more than sham operation group(P<0.05),but less than model group(P<0.05). The expression of VCAM-1mRNA was higher than sham operation group(P<0.05),but lower than model group(P<0.05).Conclusions:1.After the formation of focal cerebral ischemia-reperfusion injury in rats, the inflammatory cytokines in the ischemic brain tissue accumulate and upregulate the expression of vascular endothelial cell surface adhesion molecule.Then it manifest as the increased expression of VCAM-1mRNA and VCAM-1.2. Through decreasing the expression of VCAM-1mRNA and VCAM-1, the artificial synthetic E-selectin inhibits the adhesion between leukocytes and vascular endothelial cells,reduces inflammatory reaction, mitigates the cerebral ischemia-reperfusion injury and protects the brain tissue.