尾部悬吊对大鼠腓肠肌细胞介电特性的影响

Effects of Tail Suspension on Dielectric Properties of Cells in Isolated Rat Sural Muscle

目的在40Hz～110MHz频率范围观察模拟失重10wk大鼠离体腓肠肌细胞介电特性的改变。方法采用大鼠尾悬吊建立模拟失重模型,雄性SD大鼠随机分为模拟失重10wk的肌萎缩组和正常对照组。利用Agilent4294A阻抗分析仪测量离体大鼠腓肠肌的交流阻抗,通过频域介电谱、Cole-Cole图、介电损耗因子频谱、介电损耗角正切频谱和电导率虚部频谱的数据分析,观察模拟失重对大鼠离体腓肠肌细胞介电特性的影响。结果模拟失重10wk大鼠腓肠肌的低频介电常数εL降低,介电增量Δε减小,绝缘性降低;高频电导率κh降低,电导率增量Δκ降低,导电性降低;第一特征频率fC1减小,第二特征频率fC2增加;介电损失最大值Δε″max、损耗角正切最大值Δtgδmax和电导率虚部最大值Δκ″max均降低。结论利用频域阻抗技术可以有效地观察到模拟失重导致的腓肠肌细胞介电特性发生的改变。

Objective To study changes of dielectric properties of gastrocnemius caused by simulated weightlessness. Methods Male Sprague-Dawley rats tail suspended for 10 wk were observed to- gether with its normal control. AC impedance of isolated gastrocnemius was measured with an impedance analyzer（Agilent 4294A）. Effects of simulated weightlessness on electric properties of cells in isolated rat sural muscle were also observed by analyzing the dielectric numerical characters of the dielectric spectra ,the Cole-Cole plots, spectrum of loss factor and loss tangent, as well as spectrum of conductivity imaginary part. Results It was found that simulated weightlessness could induce certain changes： both relative permittivity at low frequency ε1 and relative permittivity increment △ε, as well as conductivity at high frequency κh and conductivity increment △κ were all reduced. The first characteristic frequency fc1 decreased, while the second characteristic frequency fc2 increased. Peak of loss factor, peak of loss tangent and the maximum of conductivity imaginary part were also reduced. Conclusion Changes of dielectric property of gastrocnemius induced by simulated weightlessness can be observed effectively by frequency domain impedance technique.