水通道蛋白4在脂多糖致大鼠脑水肿的表达及与血脑脊液屏障的关系

目的观察脂多糖（LPS）致幼年大鼠感染性脑水肿后水通道蛋白4 mRNA（AQP4mRNA）的表达变化,探讨其作用机制。方法将50只幼鼠随机分为内毒素组（40只）和对照组（10只）,内毒素组又按时间点分为6、12、24及48h4个亚组,每组均为10只。于预定时间点处死动物,制备脑组织标本。用干湿重法测定不同时间点脑组织含水量,甲酰胺法测定伊文思蓝（EB）水平,RT-PCR技术检测脑组织内AQP4 mRNA的表达。结果内毒素组脑组织含水量和EB水平明显高于对照组。LPS注射后6h,脑组织AQP4 mRNA水平的表达均明显增加,12h时达高峰,各时间点与对照组比较均有显著性差异（Pa〈0.01）。结论感染性脑水肿后脑组织中AQP4 mRNA的表达增加,且与血脑脊液屏障的破坏程度呈正相关。

Expression of Aquaporin 4 mRNA and Correlation between Aquaporin 4 mRNA and Blood Brain Barrier in Brain Edema of Rats Induced by Lipopolysaccharide

Objective To observe the expression of aquaporin-4(AQP4)mRNA in brain edema induced by endotoxin as well as to explore the mechanism of action of AQP4 mRNA.Methods A total of 50 infant rats were divided into 2 groups randomly:endotoxin group(LPS group,n=40)and normal saline group(NS group,n=10),endotoxin group was devided into 4 subgroups:6,12,24,48 h,10 infants were prepared in every subgroup.Rats were decapitated at different time point,and brain tissue samples were prepared.The water content of brain tissue was determined by measuring both wet weight and dry weight.The evans blue(EB)content of brain tissue was determined by the formamide.RT-PCR were used to investigate the expression of AQP4 mRNA.Results Compared with NS group,brain water content and brain EB content were higher in LPS group at each time point.The level of AQP4 mRNA significantly increased at 6 h subgroup after injecting LPS.The peak time of which was at 12 h.The difference of AQP4 mRNA between in LPS groups and the control group had statistic significance at every time point(P<0.01).Conclusions After injecting LPS into rats' carotid,the expression of AQP4 mRNA are up regulated.And the expression of AQP4 mRNA has positive relationship with EB content.