Effects of low frequency resonance on physiological function in rats / 医用生物力学

ABSTRACT

Objective To study the effect of continuous low frequency resonance on blood pressure, heart rate, breath rate and body temperature of the rat so as to provide basic data for the study of organs’ resonance injury and its reaction. Method Thirty two SD rats were divided into four groups randomly false vibration group, 3 Hz vibration group, 6 Hz vibration group and 21 Hz vibration group. Femoral artery intubatton was given after anaesthesia with 1.5% sodium pentobarbital. All the rats were fastened on their back on the vibration platform staying calmly for 30 min. Then the vibration groups were given sine wave vibration with 5 mm amplitude(p-p), while the blood pressure, heart rate, breath rate and body temperature of the rats were measured at 0, 1, 3, 5, 10, 30, 60, 120, 180, 240, 300 and 360 min. The above physiological data were also observed in false vibration group at corresponding time. Results Continuous low frequency resonance could cause the blood pressure, heart rate, breath rate of the rat to rise rapidly after 1 min of vibration, and to reach the maximum value after 1 min to 3 min of vibration, and then to descend gradually and to be lower than the normal value after 30 min of vibration. The body temperature of the rat did not change at the beginning of vibration, but descended gradually after 10 min of vibration. At the beginning of vibration, the effect of 6 Hz resonance on blood pressure, heart rate, breath rate was dominating, while at the later stage, 3 Hz resonance was dominating. But the effect of the two frequencies on body temperature was accordant. Conclusions Continuous low frequency resonance can cause the blood pressure, heart rate, breath rate of the rat to rise rapidly at the beginning of vibration and then to descend gradually, and it can also depress the ability of body temperature regulation in rats.