Technology Of Measuring The Brain Water Content By Specific Gravity And Study Of Rats Brain Tissue Aquaporin-4 Expression Change By Asphyxia After Cardiopulmonary Resuscitation

Partâ… Technology of Measuring the Water Content of the Brain Tissueby the Specific Gravity and Study about its Influencing FactorsObjective:To establish the liquid specific gravity column in order to measure the brain water content;To approach the influencing factors about measuring the brain water content with it.Methods:Prepare the liquid specific gravity column:make the mixed liquid A which gravity is 0.975 and liquid B which gravity is 1.065 with brombenzene and kerosene;and use each 100ml of them to prepare the liquid specific gravity,stabilize it after the stabilization of 15 minutes.To make the four standard specific gravity liquids of 100ml with the drying kalium slfuricum(K₂SO₄),and each gravity is 1.045,1.040,1.030 and 1.025.To read the height of the drop in the gravity column after 1 minute with the microamount sample injector to get the standard liquid of 5μl.According to the gravity of the standard liquid and the height in the specific gravity column,set up the linearity equation and transform the height of the tissue sample in the specific gravity column into the tissue specific gravity(SGt)with the equation.To choose the 10 SD rats,anesthetize them and kill them with the kalium chloratum(KCl)after the operation is over.To open the skull quickly and strip the meninges,put the brain tissue on the culture dish which is above the ices.To measure the gravity of the left and right brain tissue with the specific gravity column and calculate the gravity of them.To weigh the weight in wet and in dry of the surplus brain tissue and calculate the brain water content according the equation of Nelson.Results:1.To use the prepared mixed liquid to make the 10 gravity column and the coefficients of determination,the indexes of the height-gravity dependability(r)≥0.999,which manifests that the stability and homogeneity of the liquid specific gravity columns which were made in this experiment are fine.2.The results of the experiment manifest that the water content of the left and right brain in rats is almost symmetry and BWC of the corresponding brain district does not obviously have the difference.Conclusion:1.The liquid specific gravity columns which were made in this study have fine stability and homogeneity and can theoretically find the change of±0.1% tissue water content.2.Collect the samples of the low temperature in this experiment which can simplify the steps and reduce the error.It also shows that the sample which need detect in the specific gravity is smaller and it has the feature of the sensitivity and accuracy are higher.Partâ…¡Study on Dynamic Change of Aquaporin-4 and AQP4mRNAExpression Level in the Brain Tissue in Rats and the Effect of Ifenprodil on them after Cardiopulmonary ResuscitationObjective:To investigate the dynamic change of brain edema during early stage after ROSC,the role of aquaporin-4(AQP4)and AQP4mRNA in the development of brain edema and the effect of ifenprodil on them.Methods:Seventy-eight male SD rats were subjected to third groups at random: control group,CA group,NMDA group.The later two groups were respectively divided into ROSC1,3and 6hours subgroups(n=10).The cardiac arrest model in rats was duplicated by asphyxy method.The brain water content(BWC)was measured by means of gravimetric technique at ROSC1,3 and 6hours,and observed the change of the brain histomorphology at the same time.The AQP4 expression level in brain tissue was determined by semi-quantization immuno- histochemistry staining at the same time.The expression of AQP4-mRNA expression level in brain tissue was measured by RT-PCR.The Correlations were analyzed between the BWC and AQP4 expression level,the BWC and AQP4-mRNA expression level. Results:1.The BWC increased obviously atlh after ROSC in CA group.The BWC at3 and 6h after ROSC were significantly higher than that of the control group(P＜0.05).The change of morphology in brain tissure coincided with the results above.At the same time,the changes of the AQP4 and AQP4mRNA expression level was as nearly same as that of the BWC.The correlation analysis demonstrated further that the BWC was correlated apparently with the AQP4,AQP4mRNA expression level in brain tissue,(r = 0.680)(r = 0.569)(P＜0.05).2.The BWC and AQP4 expression level in brain tissue at 1h were lower than these in the same time of CA group,and with the time passing the two objects observed in NMDA CA rats were much significantly lower than those in CA rats at 3 and 6h after ROSC(P＜0.05).The correlation analysis demonstrated that the BWC was also correlated apparently with the AQP4,AQP4mRNA expression level in brain tissue within ifenprodil was executed on rats for 6h,(r=0.541)(r=0.587)(P＜0.05).Conclusion:1.The brain edema occurs at 1h after ROSC,and it gets more and more severe as the time goes by.2.The expression level of AQP4 in brain tissue is up-regulated after ROSC,the expression level of AQP4 mRNA is up-regulated as well..It is indicating that AQP4,AQP4mRNA play probably key role in the development of brain edema.3.Ifenprodil after ROSC can reduce the development of brain edema in the early stage after ROSC,the mechanism is possibly related to the down-regulation of AQP4 and AQP4 mRNA expression level in brain tissue issued by ifenprodil.