模拟失重对大鼠血液电阻率频谱特性的影响

Effect of simulated weightlessness on resistivity spectrum characteristics of rat blood

目的利用电阻抗法观察模拟失重大鼠血液电阻率变化并探讨其机制。方法实验动物分为正常对照组和模拟失重组，模拟失重采用大鼠尾部悬吊法。血液阻抗谱测量采用Agilent4294A阻抗分析仪完成。在0．01～100MHz频率范围选取80个频率点，设定每个频率点自动循环扫描测量3次取均值，交流激励信号源电压0．5V。通过Bode图、Nyquist图和Nichols图的数据分析，观察模拟失重对大鼠血液电阻率频谱特性的影响。结果血液电阻率降低：模拟失重组的低频复电阻率幅值｜ρ^＊｜0、高频复电阻率幅值｜ρ^＊｜m、复电阻率幅值增量（△｜ρ^＊｜=｜P’｜0-｜ρ^＊｜m）、相位角峰值θp幅度、低频复电阻率实部值ρ^＊0、复电阻率虚部峰值P^Hp幅度、低频复电阻率幅值对数lg｜ρ^＊｜0较对照组均降低。血液特征频率：第一特征频率fc1，和第二特征频率fc2较对照组均增加。结论模拟失重引起大鼠血浆、红细胞膜和血红蛋白的电阻率降低，导电性能增加。

Objective To observe the changes in blood resistivity of simulated weightlessness rat by electrical impedance method and to discuss its mechanism. Methods Experimental animals were divided into normal group and simulated weightlessness group. Simulated weightlessness was achieved with the method of tail-suspension. The impedance spectroscopy of blood was measured with Agilent 4294A impedance analyzer over the frequency of 0.01 - 100 MHz, and 80 frequency points in this frequency range were selected, each frequency point automatically scan measured three times to take the mean （AC excitation signal source voltage： 0.5 V）. The simulated weightlessness on blood resistivity spectral characteristics was observed by the Bode diagram, the Nyquist diagram and the Nichols diagram. Results The resistivity of the simulated weightlessness rat blood decreased, mainly in the low-frequency limiting value of the complex resistivity amplitude ｜ ρ^＊ ｜0, the high-frequency limiting value of complex resistivity amplitude ｜ρ^＊ ｜ , complex resistivity amplitude increment （△｜ρ^＊｜=｜P＇｜0-｜ρ^＊｜m ） , the amplitude of phase angle peak θp, the low- frequency limiting value of the real part of complex resistivity ρ＇0, the peak amplitude of the imaginary part of complex resistivity ρ^＊, and the amplitude logarithmic of complex resistivity at the low-frequency limitinglg ｜ρ^＊｜ 0 all decreased compared with those of the control group. The 1st and 2nd characteristic frequencies of blood （fc1 and fc2） increased respectively compared with the control group. Conclusions Simulated weightlessness might decrease the resistivity and increase the conductivityof the plasma, red cell and hemoglobin.