Experimental Research On Brain Edema And Beneficial Effect Of C-Erythropoietin In Traumatic Brain Injury Rats With Seawater Drowning

Part I The Study on the Changes of Brain Edema after Trauma Brain Injury Accompanied by Seawater Drowning in RatsObjectives:To observe the change of brain edema in traumatic brain injury(TBI)rats with seawater drowning by detecting the brain water,Na+,K+ content and the permeability of blood brain barrier(BBB).Methods:Totally 216 male rats were randomly divided into normal control group(n=6),the sham operation group(n=14),TBI group(n=98),TBI accompanied by seawater drowning group(n=98).Marmarou's weight-drop TBI model(450g,1.5m)and the method of instilling seawater into the trachea(3ml/kg)using terufusion syringe pump was used to establish an animal model of moderate closed TBI with seawater drowning.Dry-wet method was used to detect brain water content.EB assay was used to detect BBB permeability.At different time point post TBI,The brain water,Na+,K+ content and brain EB content were detected to evaluate the severity of brain edema and the permeability of BBB.Results:?As compared with that in TBI group,the brain water,Na+,EB content in TBI accompanied with seawater drowning group was significantly increased in different time points,however,the content of K+was obviously decreased.?The brain water,Na+ content of TBI group began to rise 6h after injury,reached to the peak in 48h,maintaining till 72h,14d a:fter injury return to the normal levels,however,The brain K+ content showed a fall at 6h,the lowest at 48h,14d after injury return to the normal levels.?The brain water,Na+ content of TBI accompanied by seawater began to rise 3h after injury,reached to the peak in 12h,maintaining till 7d,14d after injury still higher than the normal levels,however,The brain K+ content showed a fall at 3h,the lowest at 12h,14d after injury still lower than the normal levels.?The EB content in TBI group showed bimodal,respectively in 3h and 48h after injury.?TheEB content in TBI accompanied with seawater drowning group increased obviously 3h after injury,reached the peak at 12h,maintained to 72h,but still higher than normal at 14d after injury.Conclusions(1)Seawater drowning can increase BBB permeability and worsen traumatic brain edema(TBE)after TBI.(2)Compare to TBI group,TBI accompanied with seawater drowning rats' brain edema occurre earlier and last longer.(3)Compare to TBI group,TBI accompanied with seawater drowning rats' brain edema peak time occurre earlier and last longer.(4)TBI accompanied with seawater drowning rats occurre cellular brain edema(CBE)and vasogenic brain edema(VBE)at early stage after injury,and maintained to later period after injury.Part? Study of Correlation Between Expression of Aquaporins-4 and Cerebral Edema in TBI Rats with Seawater DrowningObjectives:To observe the expressions of AQP4 and the change of cerebral edema in TBI rats with seawater drowning and discuss their correlation.Methods:Totally 126 male SD rats were randomly divided into the sham operation group(group A,n=36),TBI group(group B,n=30),TBI accompanied by seawater drowning group(group C,n=60).qPCR,Western Blot,dry-wet method,EB method was used to determine the expression of AQP4,water content,brain content in brain cortex respectively.Finally the correlation analysis was performed about these results.Results:?As compared with that in group B,the expression levels of AQP4 around injury area in group C were obviously increased,and the expression of AQP4 started to increase at 6 hour,peaked at 24 hours(P<0.01)and the:increased AQP4 level continued to 72 hours in the group C.At day 7,the AQP4 levels still higher than the level of the sham-operated group.?The changes of AQP4 mRNA were positively correlated to those of AQP4 protein(P<0.05),also were between The changes of brain water content/The changes of brain EB content and AQP4 expression/AQP4 mRNA expression(P<0.05).Conclusions:(1)The expressions of AQP4 are induced to increase post TBI,and sea water drowning lung injury can aggravate.(2)These finding suggests strongly that AQP4 is involved in the CBE.Part ? Effect of Carbamylated Erythropoietin on Brain Edema and its Mechanism in Traumatic Brain Injury Rats with Seawater DrowningObjectives:To observe the effect of C-EPO in TBI rats with seawater drowning.Methods:Totally 108 male SD rats were randomly divided into the sham operation group,TBI accompanied by seawater drowning group,C-EPO treatment group.After successfully build of the composite model,rats were intraperitoneal injected with C-EPO 50?g/kg every 24h,or the same volume of physiological saline.Neurologic function of rats was observed by a mNSS,dry-wet weight method was used to detect brain tissue water content,EB assay was used to detect BBB permeability,HE staining was used to detect brain tissue pathological changes.Using qPCR to detect levels of AQP4 mRNA expression.Using Western Blot to detect the expression levels of AQP4 protein.Results:?Brain water content of C-EPO treatment group rats was significantly lower than the TBI group 24h,72h and7d after TBI(P<0.05).?EB content in C-EPO treatment group was significantly lower than the TBI group 6h,72h after TBI(P<0.05).?The swelling of nerve cells in treatment group is quite lighten than TBI group.?mNSS score in treatment group reduced statistically significant compared with TBI group 3,7,and 14d after injury(P<0.05).?C-EPO therapy significantly reduced the high expression levels of AQP4 after TBI.Conclusions:(1)C-EPO has a neuroprotective effect by inhibiting TBE in TBI rats with seawater drowning.(2)C-EPO probably via down-regulate of AQP-4 mRNA and protein expressions to anti-brain edema.