NF-κB和AQP-4在亚低温治疗大鼠脑出血中的作用

Down- regulation of the NF-κB and AQP-4 by Mild Hypothermia in the Brain Tissue of the Rats Following Intracerebral Hemorrhage

目的探讨亚低温对大鼠急性脑出血(intracerebral hemorrhage,ICH)后脑水肿及核转录因子(nuclear factor-κB,NF-κB)和水通道蛋白4(aquaporin-4,AQP-4)表达的影响。方法将96只健康雄性SD大鼠,采用数字表法随机分为假手术组(SO)、常温组(NT)、亚低温组(HT),每组再分为1、2、3和4天4个时间点,每个时间点8只大鼠,采用大鼠基核节注入自体不凝血制作脑出血模型。SO组和NT组大鼠控制体温在37.0±0.3℃;亚低温组在脑出血后迅速降温至33.0±0.4℃并保持2h。检测在不同时间点大鼠脑组织含水量,凝胶电泳迁移率实验(EMSA)检测NF-κB活性;Western blot法检测AQP-4蛋白的表达。结果与SO组相比较,NT组在各时间点大鼠脑含水量、NF-κB活性及AQP-4蛋白表达均明细升高,差异有统计学意义;在各时间点,HT组大鼠脑含水量、NF-κB活性及AQP-4蛋白表达均显著低于NT组(P<0.05);NF-κB的活性表达与AQP-4蛋白表达呈正相关。结论早期亚低温治疗可抑制大鼠脑出血后NF-κB活性和AQP-4蛋白的表达,从而减轻脑水肿。

Objective To elucidate the effect of mild hypothermia on brain edema and the expression of NF-κB and AQP-4 in rats after intracerebral hemorrhage.Methods Ninty six healthy male Sprague-Dawley （SD） rats were randomly （random number） divided into three groups （n =8） for experiments：sham-operated group （SO）,normothermic group （NT）,hypothermic group （HT）.Rats in each groups were examined at 4 different time points of 1,2,3 and 4 days.The intracerebral hemorrhage （ICH） model was established with stereotactic infusion of autologous blood into caudate nucleus.The rats in NT group and SO group were kept at 37.0 ±0.3℃ of body temperature.Animals in the HT group after ICH were kept at 33.0 ± 0.4℃ of body temperature for 2 hours.The brain water content was determined at different times.The NF-κB DNA-binding activity was measured by electrophoretic mobility shift assay （EMSA）.The expression of AQP-4 was detected by Western blot.Results The content of brain water and the expression of NF-κB and AQP-4 were significantly higher in NT group than those in SO group at 4 different time points （P ＜ 0.05）.There was statistically difference in the content of brain water and the expression of NF-κB and AQP-4 between HT groups and NT group.The correlation analysis between NF-κB and AQP-4 was positively relative.Conclusion Hypothermia can relieve the severity of brain damage in rats after ICH by down-regulating the NF-κB DNA-binding activity and protein level of AQP-4.