| Infectious brain edema occurred during onset of infectious diease. It was an important cause that made children with infectious central nervous system ( CNS ) disease dying and disable,and it also was one of the problems that needed doctors to resolve immediately.In recent years,CNS had been found to have the similiar functions with other organa,such as presentation of antigen, formation of antibodity, synthesis of complement and cytokines,and phagocytic function.In order to study the establishment of animal models of infectious brain edema and its pathogenesis,most researchers adopt open injury to CNS or cell culture in vitro.The ways were direct but could not echolize the infectious process of body in via objectively.At present, the study in adhesion molecules(AM) and cytokin had not been developed generally on the base of animal models inducing CNS infection through blood streem.How to establish the animal model of infectious brain edema by echomoting the happening of disease in human was the first problem that needed to be resolved.Lipopolysaccharide(LPS,endotoxin)-the essential pathogenetic component of gram-negative bacterium-was injected into artery.LPS reached brain tissue and caused pathological change. Through echomotizing the onset and development of illness in human body, aconsolidated,stable and repeatable animal model of infectious brain edema was expected to be established.Based on this, drug treatment was applied.lt would be helpful to explore the pathogenesis of infectious brain edema by detecting expression of AM and cytokin in via body objectively and dynamically.Intercellular adhesion molecule-1 (1C AM-1) was an importmant component in immunoglobulin famility of adhesion molecules(AM).ICAM-l was expressed on vascular endothelial cells widespreadly in CNS.lt could play an important role in adhesion and transition of leukocyte,and participate in inflammatory reactions. AM could be induced to express by many factors,such as lipopolysaccharide(LPS) and inflammatory cytokines(IL-l, TNF- a , IL-8, IFN- Y ),hypoxia,reperfusion after ischemia,and so on.Cytokines could not only exert bioactivity to production and control of AM ,but also affect each other in their induction, regulation of receptor ,and exertion of bioactivity . So an abound and sophisticated cytokin network was formed.AM and TNF-cc x IL-8 could play an important role in intervening inflammatory process of infectious brain edema.To explore their effects and relationship would help us understand pathogenesis of CNS infectious disease,provide new measures to prevention and theraphy.METHODS: 150 healthy adult SD rats were randomly divided into three groups : normal saline group(NS group,n=50);LPS group(LPS group,n=50);dexamethamone group(DXM group,n=50).Each group was then divided into five groups:4h;6h;12h;24h;48h,and each group had 10 rats.The infectious brain edema was established by applying LPS carotid injection.Rats were decapitated at different time point,and brain tissue samples were prepared after rats were perfused with ice normal saline. So the water content,evans blue content,TNF- a content,IL-8 content of brain tissue, the expression of ICAM-1 were detected in each group at different time point.RESULTS: (1) Histopathological change:In LPS group, with lightmicroscope,it could be found that the space among vascular began broaden and inflammatory cells infitrated.In severe cases,astrogliocyte and gliocyte became tumefied,neurocyte was degenerated.In DXM group,brain cells began less tumefacient,pathological change became attenuated. (2)Brain water content and EB content:brain water content and EB content in NS group were relatively stable and had no significant difference in each time point(.P>0.05) .In LPS group,brain water content and EB content elevated maximally at 6h and maintained higher levels at 48h compared with NS group and DXM group (P<0.01) .At each time point ,brain water content and EB content in DXM group were lower than that in LPS group ( P<0.05 ) , but still higher than tha...
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