FMR1基因敲除小鼠脑组织中Nav1．1的改变及其意义

Expression of Navl.1 and its significance in brain tissues of FMR1 knockout mice

目的探讨Nay1．1在脆性X综合征（FXS）癫痫易感性增加中的可能作用。方法选用2周龄、4周龄的FVB品系FMRJ基因敲除型小鼠（KO2周和KO4周）及同龄野生型小鼠（WT2周和WT4周）为实验对象，应用免疫组化染色方法检测小鼠大脑纹状皮质、颞听皮质、梨状皮质、海马CA1区、CA3区及齿状回中Nav1．1的表达：应用Westernblotting检测小鼠大脑皮层和海马组织Nayl．1蛋白含量。结果免疫组化染色结果显示：KO2周和KO4周小鼠大脑纹状皮质、颞听皮质、梨状皮质、海马CAl区及齿状回区Navl．1表达的平均吸光度值（2周：0．058±0．006、0．054±0．006、0．130±O．015、0．090±0．009、0．142±O．010；4周：0．066±O．007、0．060±O．007、0．159±0．018、0．102±0．015、0．192±0．025）分别较WT2周和WT4周小鼠（2周：0．049±0．007、O．046±0．007、0．118±0．012、O．080±0．009、0．133±0．010；4周：0．051±0．007、0．048±0．005、0．127±0．012、0．089±0．012、0．175±0．024）明显增多．差异均有统计学意义（P〈0．05）。Western blotting检测结果显示：KO2周和KO4周小鼠大脑皮层、海马组织Nav1．1蛋白含量（2周：0．635±0．082、0．954±0．111：4周：0．819±0．064、1．145±0．159）分别较WT2周和WT4周小鼠（2周：0．382±0．025、0．555±0．056；4周：0．550±0．040、0．847±0．127）明显增多，差异均有统计学意义（P〈0．05）。结论Nav1．1表达增多可能是引起FXS模型小鼠癫痫易感性增加的原因之一。

Objective To explore the possible role of Navl.1 in the pathogenesis of increased susceptibility to epileptic seizures in FMR1 knockout （FMR1 KO） mice. Methods FVB strain FMR1 KO mice and wild type （WT） controls at ages of 2 and 4 weeks old were chosen; immunohistoehemistry was used to determine the expression of Nay 1.1 in different brain regions （striate cortex, temporal cortex, piriform cortex, hippocampus CA1, CA3 and dentate gyrus）, and Western blotting was used to determine the Nay1.1 level in the cerebral acustici cortex and hippocampus. Results The mean optical density of Nav1.1 was significantly increased in the striate cortex, temporal acustici cortex, piriform cortex, regions of CA1 and dentate gyrus in FMR1 KO mice at ages of 2 and 4weeks （2 weeks： 0.058±0.006, 0.054± 0.006, 0.130±0.015, 0.090±0.009 and 0.142±0.010, 4 weeks： 0.066±0.007, 0.060±0.007, 0.159±0.018, 0.102±0.015 and 0.192±0.025） as compared with the age-matched WT mice （2 weeks： 0.049±0.007, 0.046±0.007, 0.118±0.012, 0.080±0.009 and 0.133±0.010; 4 weeks： 0.051±0.007, 0.048±0.005, 0.127± 0.012, 0.089±0.012 and 0.175±0.024, P〈0.05）. The levels of Navl.1 in the cerebral cortex and hippocampus in FMR1 KO mice at ages of 2 and 4 weeks （2 weeks： 0.635±0.082 and 0.954±0.111, 4 weeks： 0.819 ±0.064 and 1.145 ±0.159） were also significantly increased as compared with the age-matched WT mice （2 weeks： 0.382±0.025 and 0.555±0.056; 4 weeks： 0.550±0.040 and 0.847±0.127,P〈0.05）. Conclusion Increased expression of Navl.1 might play an important role in the increased susceptibility to epileptic seizures in FMR1 KO mice.