Study Of The Electrical Impedance Spectral Characteristics And The Theoretical Model Of The Rat Blood On Simulated Weightlessness

Objective The AC impedance method was used to evaluate the characteristic changesof electrical impedance spectrum of rat blood on simulated weightlessness. The present studyis arm to create the mathematical model, the mathematical model and circuit modelparameters for the blood cells based on the blood electrical impedance spectroscopy. Furthermore, the study shows the electrophysiological mechanism of the changes in blood cells forweightlessness anemia to provide referential methods and electrophysiological indices for thediagnosis and treatment of anemia.Methods Rats were hanged by the tails for60days to simulate the animal model ofweightlessness. The samples of blood were collected from common carotid artery of rats. Theinput impedance of blood was determined by Agilent4292A Impedance Analyzer.80pointswere selected over the wide frequency range from10kHz to100MHz. The spectrumparameters in both the normal group and the simulated weightlessness group were obtained bymeasuring the impedance of blood. Created a blood electrical impedance spectral featureextraction method, and established the characteristic parameters of the control group and thesimulated weightlessness group, then statistical method was used to compare the differencebetween two groups, it can lay the foundation for the electrical characteristics of anemia bloodcells’ detection instrument development. Then the Cole-Cole mathematical formula combinedwith the nonlinear numerical calculation and curve fitting was used to establish themathematical model for blood electrical impedance spectrum of simulated weightlessness rats.Moreover, the equivalent circuit model was created by relevant adjustment and fitting analysisof circuit based on the components（extracellular resistance Re, intracellular electricalimpedance of Ri electrical impedance of the membrane capacitance C_m）.Result（1） The electrical impedance of blood in simulated weightlessness rats is lower comparedto control group. Low-frequency complex impedance real part of the value Z’0, thereal part of the value of high-frequency complex impedance Z’∞, the low-frequencyelectrical impedance amplitude modulus values of|Z*|0high-frequency electrical impedance amplitude modulus value|Z^*|_∞, the real part of the impedance magnitudeof relaxation ΔZ’, impedance amplitude mode relaxation amplitude Δ|Z*|, and low-frequency impedance amplitude mode value of the number of the Log|Z*|0, reducedby14.90%,6.10%,14.54%,6.10%,23.63%,22.48%,3.09%.（2）The characteristic frequency of electrical impedance spectrum is increased. The firstcharacteristic frequency f_C1increase23.81%and second characteristic frequency f_C2increase4.52%.（3） Both the imaginary part of complex impedance peak and phase angle peak withoutconsidering the negative sign and magnitude of comparison are less than the normalgroup. The imaginary part of complex impedance peak Z"Pdecreased by25.84%,19.05%reduction in the curvature of the phase angle the peak θP/rad, the angle phaseangle peak θP/deg16.51%reduction（4） The electrical impedance characteristics of the blood from rats after simulatedweightlessness meet the laws of the Cole-Cole mathematical model. Impedance high-frequency limit R∞decreased by19.52%, the first impedance increment ΔR1reducedby27.50%,21.82%reduction in the second impedance increment ΔR2; the firstrelaxation scattering angle α1increased by12.50%, the second relaxation scatteringangle α2increase by0.07%.（5） Electrical impedance characteristics of the blood from rats after simulatedweightlessness are in line with the law of the electrical impedance of the fivecomponent equivalent circuit model. Simulated weightlessness five parameters: theextracellular resistance Re, intracellular resistance Ri, the membrane capacitance C_m,the membrane resistance Rm, the cells’ capacitor Ci are lower than which in normalgroup,and the percentages are:14.35%,3.03%,90%,6.98%,6.55%Conclusion（1）The electrical impedance characteristics of blood is complied with the electric field,and the electrical impedance characteristics of rat blood cell is significantly differedfrom the blood sample of control group after simulated weightlessness.（2） Simulated weightlessness was responsible for the decreasing of blood resistivity andincreasing of blood conductive property.（3） Two characteristic frequencies (f_C1, f_C2) of the rat blood are increased after simulatedweightlessness.（4）The impedance parameters of equivalent circuit model, got by curve fitting, such assimulated weightlessness rat blood mathematical model and five-element which canreflect the discipline that weightlessness blood response to the alternating electricfield impedance and the characteristics of the domain blood electrophysiology data.