| ObjectiveDuring ischemia - reperfusion injury ( I/R) , which endogenetic mechanisms the central nervous system ( CNS) to bring into for self-protection are not well known nowdays. As a route treatment for hy-poxia during anesthesia, Preoxygenation's effects and mechanisms remain uncertain. So it is important to clear these problem for the prevention and treatment of brain injury.In this investigation, by means of fluorescence polarization ^ immu-nohistochemistry and light electron microscope technique, experiment animal and glibenclamide ( specific blocking agent of ATP - sensitive potassium channels) and pinacidil ( specific opening agent of ATP -sensitive potassium channels) were appliced. We observed the opening condition of ATP - sensitive potassium channels ( KATP) ^ nitric oxide (NO) of mi tochondrion^ membrane fluidity Nc - fos^HO - 1 (heme ox-ygenase -1) and histopathology of brain cortex during simple hypoxia- reoxygen ^preoxy gen - hypoxia - reoxygen and pinacidil - hypoxia- reoxygen, tried to find out the effects and probable mechanisms of preoxygen and KATP on hypoxia - reoxygen brain injury, in order to pro-vide science base for prevention of hypoxia - reoxygen brain injury to clinical anesthesia and other correlation subject.Methods1. Animals and groupsWister rats,230 ~300g of either sex,from the Department of Laboratory Animals, China Medical University. The fourty two rats were divided randomly into seven groups.Group I , samoperation ( control group ) ; intracerebralventricular (icv) 0. 1% Dimathyl sulfoxide(DMSO)10 ul.Group fl , simple hypoxia - reoxygen group: after hypoxia for 30 min, reoxygen for 60 min.Group HI ,pinacidil - hypoxia - reoxygen group: icv pinacidil 10 ul,30 min later,acted as groupII.GroupIV, glibenclamide - pinacidil - hypoxia - reoxygen group: icv glibenclamide 10 ul,20 min later, acted as group HI.Group V , preoxygen - hypoxia - reoxygen group: preoxygen for 30 min, acted as group II.Group VI, pinacidil - preoxygen - hypoxia - reoxygen group: icv pinacidil 10 ul,30 min later,acted as groupV.Group VH, glibenclamide - preoxygen - hypoxia - reoxygen group: icv glibenclamide 10 ul,30 min later,acted as groupV.2. Preoxygenation - hypoxia - reoxygen experiment2.1. Preoxygenation experiment:rats are put into 100cm x 100cm x 100cm oxygen cabin ( having sodalime) , blowing pure oxygen from air inlet, adjusting the oxygen concentration to maintenance it at 95 ?2% and lasting for 30 min.2.2. Hypoxia experiment: rats are put into above oxygen cabin with 6 ± 2% oxygen concentration lasting for 30 min.2.3. Reoxygen experiment: rats are put into above oxygen cabin with 95 ± 2% oxygen concentration lasting for 60 rain.3. Detect methods of the specimen3.1. Assay methods of mitochondria membrane fluidity: the technique of fluorescence polarization.3.2. NO of the brain mitochondrion are measured by the technique of azotic acid recovery.3.3. Immunohistochemistry: We use an affinity - purified c - fos and HO - 1 antibodies and peroxodase marked streptavidin to detect the presence of c - fos and HO - 1 possitive cells in the brain. Pathology image analyse instruments are used for determinant of results, nucleus of c - fos positive cells have palm snuffcoloured grain. HO - 1 positive cells are those the nucleus and cell plasm having palm snuff-coloured grain, percentage of each positive signal area(area% ) is determined for express range of positive signal. Measure three visual fields of each sections, count average value.3.4. Histology:The brain samples are fixed and embedded as reported method. 4 um - sections are cut and stained with a hematoxylin-eosin(HE) for histologic examination, section preparatio are fillet-inged with LKB - ultramicrotome, and after stained with both lead and uranium, observed with electron microscopy ( TEM ).4. StatisticsData are expressed as mean ± standard deviation ( x ± s ). Statistics analysis is performed with One - Way analysis of variation (ANO-VA) ,P <0.05 is consid...
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