Changes Of Intercellular Adhesion Molecule-1in Cerebral Ischemia And Reperfusion Injury Under Hyperglycemia

Objective Hyperglycemia contributes to the aggravated Cerebral ischemia andreperfusion injury,but the mechanism for increased brain damage is not clear.Observe theexpression of ICAM-1,analysis the effect of ICAM-1in the brain ischemic rats. withhyperglycemia by manufacturing rat model of cerebral ischemia and reperfusion injury underhyperglycemia.Explore the possible molecular mechanisms of astrocyte and ICAM-1in thebrain ischemia rats with hyperglycemia.Methods SD rats were randomly divided into3groups:the sham operation group,normal cerebral ischemia-reperfusion group(normolglycemia),and diabetic cerebralischemia-reperfusion group (hyperglycemic). Rat hyperglycemia was induced by singleinjection of55mg/kg streptozocin(STZ). Both hyperglycemic and normoglycemic rats weresubjected to a8minutes of forebrain ischemia induced by clamping bilateral common carotidarteries and bleeding hypotension to45-50mmHg. Reperfusion was introduced by reinfusingthe shed blood and by releasing the clamps placed around the carotid arteries. Histologicalchanges of neurons and astrocytes and expression of glial fibrillary acidic protein (GFAP)andICAM-1, Cellular localization of ICAM-1at frontal cortex were detected after8minutesclamping bilateral common carotid arteries,24hours、72hours and144hours of recirculationby pathohistology, immunofluorescence,Western blot,RT-PCR and in situ hybridization.Results Histological changes: neuronal and astrocyte obvious edema in diabeticcerebral ischemia-reperfusion group,neuron apoptosis appear in144hours of recirculation。Nissl bodies series dissolve、disappeare and reduce,structure is unclear stained lighter Comparing with the normolglycemia. Detect of ICAM-1: By Western blot and RT-PCR wefound that the expression of ICAM-1of frontal cortex in normolglycemia is more thansham,obviously increase in hyperglycemic Comparing with the Sham and normolglycemia.Detect of GFAP.:Western blot and immunofluorescence results show that the expression ofGFAP obviously increase Comparing with the normolglycemia at the same reperfusion timepoints, Expression of GFAP is the most, process and largest number of astrocytes weredetected in144hours of recirculation. Detect of PCNA: By immunofluorescence stainingwe found that minority of PCNA-positive cells of frontal cortex in Sham,PCNA-positive cellsincrease Comparing with the Sham, PCNA-positive cells increase obviously Comparing withthe Sham and normolglycemia.Immunoreactive double-labeled cells of PCNA and GFAPappear in each group,but there is no significant change,no obviously increase or decrease. Byimmunofluorescence staining and in situ hybridization we found that that numbers ofICAM-1-positive cells was largest in hyperglycemic,there is no immunoreactivedouble-labeled cells of ICAM-1and GFAP in each group, minority immunoreactivedouble-labeled cells of ICAM-1and Neun appear in sham, double-labeled cells increased innormolglycemic, double-labeled cells increased obviously in hyperglycemic Comparing withthe Sham and normolglycemia.Conclusion neurons edema and degeneration at frontal cortex were detected after8minutes clamping bilateral common carotid arteries,24hours、72hours and144hours ofrecirculation, hyperglycemia aggravata neuronal damage in the region.Not only neuronsdamage aggravated,but also Enlarged cell body, lengthened and thicken process ofastrocytes,expression of GFAP increased. GFAP-positive cells increased, cell body EnlargedComparing with the normolglycemia in144hours of recirculation. ICAM-1protein andICAM-1mRNA increased at frontal cortex were detected after8minutes clamping bilateralcommon carotid arteries,24hours、72hours and144hours of recirculation, hyperglycemicincreased higher than normolglycemia. Suggest that cerebral ischemia and reperfusion injury can activate the expression of ICAM-1in brain tissue, ICAM-1mediated brain injury,Hyperglycemia contributes to the aggravated Cerebral ischemia and reperfusion injury may beassociated with the expression of ICAM-1-mediated inflammatory response.In thisexperiment, ICAM-1involved in neuronal damage,but astrocyte may not play a major role...