Experimental Studies On The Expression Of VWF And Laminin In Microvasculature And The Role Of Inflammatory Mediators After Global Cerebral Ischemia-reperfusion

Reperfusion after cerebral ichemia can induce more serious damage than that of cerebral ischemia itself.An inflammatory response occurring after the reestablishment of circulation has causative role in this reperfusion.The recruitment of neutrophils to the area of ischemia ,involves the coordinated appearce of multiple proteins.The expression of intercellular adhesion molecules,cytokines is increased ,and the function and integrity of the microvessels are damaged.then the normal cerebral blood is not supplied properly. So it is very important to investigate the microvascular lesions after cerebral ishemia reperfusion and the mechanism of endothelial inflammation . The study investigate not only the change of microvascular intergrity but also the alterations of intercellular adhesion molecules and cytokines after global cerebral ischemia-reperfusion in rats. In this way.we want to interpret the inflammatory molecular mechanism of cerebral ischemia- reperfusion.In this study ,the heathy male Sprague-Dawley (SD) rats were divided intotwo groups randomly,one was cerebral ischemia-reperfusion group and anotherwas sham operated control group. The global cerebral ischemia-reperfusion model was formed by occluding three arteries(30 min) and reperfuse in rats(lh> 3hs 6h^ 12h> 24tu -. 48h, 72h).Laminin and Vffl factor related antigen(von Willebrand Factor,vWF) were detected by immunohistochemical SABC staining method,in oder to mark the changes of microvascular damage and repair after cerebral ischemia-reperfusion.The alterations of IL-1 ?and IL-6 were evaluated by immunohistochemical S-P staining.and we detected the expression of P-selectin mRNA and IL-8 mRNA in situ hybridization.The findings of experiments are lined in the following.1.The experiment of microvascular injury and repair:(l)Positive immuno reactivity of vWF was on microvascular endothelial cells surf ace. At Ih after cerebral ischemia-reperfusion,the express of vWF in microvascular endothelial cells began to decrease., then slightly decreased at 3h and the lowest at 24-48h(P<0.01)after reperfusion.The express of vWF increased at 72h after reperfusion but still lower than control level.There was statistical significance among the different groups (P<0.01). vWF immunoreactivity was strong positive in every sham operated central group.and There was no statistical significance among the different groups(P>0.05). (2) Laminin was in microvascular basal lamina. At Ih after cerebral ischemia-reperfusion,the express degree of laminin in microvascular endothelial cells began to decrease., then slightly decreased at 3h and the lowest at 24~48h(P<0.01)after reperfusion.The express of laminin increased at 72h step by step after reperfusion but still lower than control level. There was statistical significance among the different groups (P<0.01). Laminin immunoreactivity was strong positive in every sham operated control group, and There was no statistical significance among the different groups(P>0.05).2.IL-1 P and IL-6 immunohistrochemitry: (l)The expression of IL-1 3 and incresed sligtly at Ih after global ischernia/reperfusion(P<0.05),then increased dramatically and reached peak at 6-12h after reperfusion. There was statistical significance among the different groups (P<0.01). The positive immunoreactivitywas most at microvascular endothelial cells. (2)The expression of IL-6 was later than that of IL-1 $ ,which increased at 3h and peaked at 24-48h after reperfusion.The positive immunoreactivity was most obvious at microvascular endothelial cells.3.The expression of EL-8 mRNA and P-selectin mRNA in situ hybridization: (l)P-selectin mRNA was not detected in sham operated control group.lt was detected as early as Ih and then slightly increased.The expression of P-selectin mRNA peaked at 12-24h after global ischemia-reperfusion of three vessel occlusion model. The difference of each group has statistical significance(P<0.01).Positove cells was most in microvascular endo...