Study Of The Expression Of AQP-4in The Brain Edema Of Rat Brain Abscess Model With The Treatment Of Hyperbairc Oxygen

Objective:Brain abscess is one of the most life-threatening infections in thecentral nervous system and maintains one of the common neurosurgicalemergencies. Brain edema secondary to brain abscess can lead to acuteintracranial hypertension, which is one of the most important factorsaffecting prognosis. Hyperbaric oxygen therapy (HBO) means that in acircumstance of higher atmosphere pressure than normal, treatment fordisease inside organisms is achieved by the inhalation of pure oxygenwith the same pressure as the circumstance. Concurrently it is acceptedthat HBO is effective for cerebral hemorrhage and cerebral infarction.Aquaporins (AQP) constitutes a penetrating channel with intrinsicproteins inside cellular membrane for the transportation of water. Till nowin AQP family thirteen members (AQP-0-AQP-12) have been identifiedin mammals and amphibians animals, among which AQP-4expressed inglial cells in mammals. It is proven that the low expression of AQP-4innormal brain cells can be significantly. It is commonly accepted that HBOcan alleviate brain edema caused by brain abscess. But the expression ofAQP-4in brain edema after HBO remains elusive.In this study, rat model of brain edema secondary to brain abscesswas built with the right subcortical vaccination of standard strains ofStaphylococcus aureus, and we analyzed the water content and AQP-4expression in the brain edema around brain abscess after HBO. Thisstudy was intended to clarify the association between HBO and AQP-4, and provide evidence for clinical practice.Methods:50Wistar rats without consideration of gender (n=50) wererandomly divided into HBO group (n=25) and non-HBO group (n=25),and another10rats participated as controls. On the3thd，7thd，9thd，11thdand17thd after bacterial vaccination in HBO group and non-HBO group,we analyzed water content, AQP-4mRNA and immunochemistry ofAQP-4of the brain edema around the brain abscess separately.Results:1. Analysis of water content of the brain edemaThe water content of rat brain edema reached its peak on the7thdayand declined gradually. After bacterial vaccination, the water contents inHBO group and non-HBO group were both significantly higher than thecontrol group（P＜0.05）. While the water contents in HBO group weresignificantly lower than non-HBO group on any of the analysis days（P＜0.05）.2. AQP-4mRNA of the brain edemaAQP-4mRNA reached its peak on the7thday and declined gradually,which was parallel with the water contents. After bacterial vaccination,AQP-4mRNA in HBO group and non-HBO group were bothsignificantly higher than the control groups（P＜0.05）. While AQP-4mRNA in HBO group were significantly lower than non-HBO group onany of the analysis days（P＜0.05）.3. Immunochemistry of AQP-4of brain edemaGray value of AQP-4of brain edema was the lowest on the7thdayand rose gradually. After bacterial vaccination, gray value of AQP-4inHBO group and non-HBO group were both significantly lower than the control groups（P＜0.05）. While gray value of AQP-4in HBO groupwere significantly higher than non-HBO group on any of the analysisdays（P＜0.05）.Conclusion:1. In the brain edema around rat brain abscess, the water contents arepositively correlated with AQP mRNA.2. The therapy of HBO in rat brain abscess model can decreaseAQP-4mRNA and down-regulate the expression of AQP-4, therebyalleviate the brain edema.