The Temporal And Spatial Profiles Of Ischemic Neuron Glial Reaction And TGF β Expression In A Rat Model Of Focal Cerebral Ischemia/Reperfusion

Background and purpose The existence of ischemic penumbra has illuminated the gloomy prospect of stroke treatment. Experimental data show reduced infarct volume by early restoration of blood supply. Available data of the ischemic penumbra are obtained from researches on CBF, brain metabolism and electrophysiological activity. We systematically studied the temporal and spatial profiles of ischemic neurons, gilal reaction and TGF expression in the penumbra and ischemic core of focal cerebral ischemia/reperfusion with the nylon suture model.Designs and observation items Experiment 1: the study of pathological methods for viewing ischemic penumbra. Male adult Wistar rats were randomly divided into 7 groups: the normal control, pseudo-operation, O2R0,O2R0.5, O2R2, O2R4, and O2R24, 6 animals for each group. After finishing the ischemic model, animals were allowed to survive different periods for reperfusion, and followed by special autopsy. Brain tissue were stained with special and ordinary method for calculation of areas of early ischemic core. The criteria for pathological penumbra were established through the comparison of the results obtained by special and ordinary stain methods. Experiment 2: the systematically study of the ischemic penumbra after focal cerebral ischemia and reperfusion. Male adult Wistar rats were randomly deviled into 12 groups: the normal control, pseudo-operation, O2R0, O2R0.5, O2R2, O2R4, O2R8, O2R24, O2R48, O2R96, O24R0, and O4R24, there were 6 animals for each group. Animals were allowed to survive different periods before perfusion-fixed. The observation items included the areas of penumbra, ischemic core and infarcts, the number and morphological manifestation of neurons and glials in the ischemic core and penumbra, apoptosis in the ischemic tissue, and the expression of TGF in the injured brain.Methods The ischemia/reperfusion model were produced by the intraluminal suture method. The argyrophil III method were used for demonstration of dark neurons and early ischemic core. Ordinary neuropathological method included procedures of paraffin section, ultrathin and semithin section, HE, TB, and LFB staining, uranyl and lead staining. Lectinhistochemistry and immunohistochemistry were used for demonstration of reactive microglia and astrocyte, and the expression of TGF was also studied by immunohistochemistry. Apoptosis of ischemic nerve cells were demonstrated by the methods of TUNEL, Hoechst 33342, and ultrastructure. Area calculation and cell count were done through an image analysis system. ANOVA in a statistical software of SPSS were used for data analysis.Results 1. Suture model produced stable infarct in rats. The infarct area culminates after 24h reperfusion, during the 48h and 96h reperfusion the infarction were further developed, but the infarct area remain stable. The reperfusion window for this focal ischemia/reperfusion model is lesser than 4 hours. 2. The argyrophil III method could demonstrate early ischemic changes of neurons. The area of dark neurons...