Correlative Study Of Brain Water Content And Aquaporin-4 Expression Level In The Brain Tissue In CPCR Rats By Asphyxia Method

ObjectiveDuring the cardiopulmonary cerebral resuscitation,(CPCR),the cerebral edema plays an important role in the prognosis,So it is very important to study the etiological factor..Nowadays,the therapeutics bounds to the use of dehydrate and the decompression.We still have not enough doucuments in the mechanism of cerebral edema during CPCR . Till now ,the study of aquaporin (AQP) shows that the AQP is an important way for the water transport. It maybe participate in many kinds of cerebral edema in different disease.The AQP is a tunnel protein ,it can mediate the free water to convert between the biomembrane.It is the main channel for water to enter and leave the cell.In the brain There are two kinds of AQPs in the brain,the AQP1 and AQP4,the AQP4 is more important. We now have many doucuments to confirm that the AQP4 participate in the cerebral edema in the cerebral insult,,the cerbral infarction,the cerebral hemorrhage and the water intoxication.but we still have no evidence in the expression and the function of AQP4 in CPCR.In this experimentation,Firstly,we duplicate the cardiac arrest model in rat by asphyxia method.and we run the CRCR,Then according to the result of the rats,we measure the brain water content(BWC),to know the cerebral edema in different groups.then by using the immunohistochemistry(ISH)and the western bolt (WB),we can know the expression of AQP4 in CPCR rats , Finally we can investigate the correlation between the The brain water content(BWC)and the expression level of AQP4．So we try to analyse the contribution of the AQP-4 during the CPCR.Methods 1(?) Rats and the groupsAltogeher 33 healthy winstar cats, were divided into four groups at random: (the successful resuscitation group ,the failure group ,the control group)2(?) Duplicate the rat model of CPCRBy asphyxy method :First we anesth the rat ,then intube the carotid artery ,the femoral vein and the trachea and connect with the electrocardiogram monitor and the respirator, By closing the rat's trachea,We can make the rat cardiopalmus and resporation stoped ,then we can establish the rat model of CPCR.3(?) Get the brain tissuesWe make the classic CRCR(including the cardiac compression,and mechanical ventilation)to the rats, the CPCR will be lasted for at least 30minutes after the rat got alive or dead (the successful group and the failure group), (for the control group,we just make them anesthetized and intubated as we do in the other two groups.).we filling the vein with paraformaldehyde (PFA) to fix the brain tissue ,then we dissect the brain to get the tissue we need.to do immunohistochemistryWe filling the vein with natrii chlridi 250ml to get the brain tissue to do western-blot test and BWC determination.4(?) Analyse the dataThe brain water content(BWC) was measured by means of wet-to-dry and The AQP4 expression level in brain tissue was assessed by semi-quantization immuno-histochemistry staining at the same time.by using the software Chemilmager 5500 V2．03 we get the gray scale numbers of AQP-4 in different groups ,then we use thesoftware SPSS13．0,make analysis of variance;(ANOVA) to analyse the gray scalenumbers among different groups . The Correlation was analyzed between the BWC and AQP4 expression level.Results 1(?) The. Duplication of the rat model of CPCR was success.The change tendency of basic vital signs(MAP and HR) during CPCR among the three groups was nearly same.2(?) The BWC increased obviously in the failure group .and the BWC was almost the same among the other two groups . The BWC in the failure group was significantly higher than those of the other two groups (P<0．05) 3(?) The AQP4 expression level increased obviously in the failure group .and the level was almost the same among the other two groups . The level in the failure group was significantly higher than those of the other two groups (P<0．05) 4(?) The BWC and AQP4 expression level in brain tissue were not significantly different at the CPCR rats The correlation analysis demonstrated that the BWC was also correlated apparently with the AQP4 expressionlevel in brain tissue when hypothermia was executed on rats for 6h (r=0．905, P<0．01) .Conclusion1(?) The duplication of the cardiac arrest model in rat by asphyxiamethod was successful, and the model was stable fundamentally.2(?) The brain edema has formed in the CPCR, and it.It is positively correlated with the AQP4 expressionlevel in brain tissue, indicating that AQP4 participates probably in the development of brain edema.The AQP4 is harmful to the cerebral tissues,maybe due to its ability to cause cerebral edema.