摘要目的 观察大鼠液压冲击脑损伤核因子E2相关因子2(Nrf2)-抗氧化反应元件(ARE)信号通路及其下游因子血红素氧化酶-1(HO-1) 和磷酸酰胺腺嘌呤二核苷酸醌氧化还原酶-1(NQO-1)时程表达变化.方法 成年雄性SD大鼠56只,制作液压冲击颅脑损伤模型,术后1、6、12、24h、3、7d对大鼠进行神经功能评分,用干湿重法测定脑含水量;Western blot测定胞质、胞核Nrf2蛋白以及HO-1、NQO-1蛋白表达;实时荧光定量聚合酶链反应(FQ-PCR)测定Nrf2-mRNA表达.结果 创伤性脑损伤(TBI)组脑含水量于冲击伤后6h开始增加[(78.98±0.12)%],24h达高峰(82.98±0.62)%],3d开始下降[(82.26±0.72)%],神经功能评分趋势与之相反,24h下降至最低值(2.78±0.66),差异均有统计学意义(F=98.712、78.806,P=0.000).Western blot证实TBI组胞核Nrf2于1h开始升高(0.82±0.18),24h达到高峰(1.87±0.82),3d时降低(1.42±0.55),而胞质Nrf2自12h开始持续走低(1.14±0.22),呈相反趋势,差异均有统计学意义(F=11.566、17.928,P=0.001).HO-1和NQO-1蛋白表达与胞核Nrf2蛋白趋势一致(F=16.175、12.694,P=0.001).FQ-PCR结果显示TBI组冲击伤后各时间点Nrf2-mRNA表达水平无明显变化(F=0.802,P=0.968).结论 大鼠脑液压冲击伤Nrf2-ARE通路激活,可能在创伤性颅脑损伤中发挥抗氧化应激损伤作用.

abstractsObjective To investigate the time-course expression of nuclear factor E2 related factor 2 (Nrf2)-antioxidant response element (ARE) pathway and its downstream factors in rats following fluid percussion brain injury.Methods The experimental models were established in 56 adult rats.The water content and the expression levels of Nrf2 nucleoprotein and cytoplasmic proteins,heme oxygenase-1 (HO-1) and nicotinamide adenine dinucleotide phosphate (NADPH)-quinone oxidoreductase 1 (NQO-1) proteins were measured with dry-wet measure,Western blotting and reverse transcription-polymerase chain reaction (RT-PCR) at 1st,6th,12th,24th h,and 3rd,and 7th day after operation,respectively.Results As compared with normal control group,the water content in traumatic brain injury (TBI) group was increased from (78.98±0.12)% at 6th h,reached the peak at 24th h[(82.98±0.62)%],and began to drop at 3rd day [(82.26±0.72)%,F=98.712,P=0.000].Neuronal function score was decreased to the lowest level at 24th h [(2.78±0.66)],having an opposite trend with that of water content.Western blotting showed Nrf2 nucleoprotein,HO-1 and NQO-1 proteins had the same expression tendency,increasing from 1st h (0.82±0.18;0.66±0.18;0.52±0.10),reaching the maximum at 24th h (1.87±0.82;1.56±0.44;1.36±0.61),and dropping at 3rd day (1.42±0.55;1.16±0.31;1.08±0.15) (F=11.566;16.175;12.694,P=0.001).Nrf2 cytoplasmic protein continued to decrease from 12th h [(1.14±0.22)].RT-PCR showed that there were no significant differences in Nrf2 mRNA levels at different time points of TBI group (F=0.802,P=0.968).Conclusion Nrf2-ARE pathway is activated in rats following fluid percussion injury,which means that Nrf2-ARE signaling pathway may involve in the neuroprotection of antioxidative stress following TBI.