Microcirculatory Changes by Laser Doppler after Infrared Heating over Acupuncture Points – Relevance to Moxibustion

Backgrounds: Moxibustion is a commonly used treatment in traditional Chinese medicine (TCM) that involves the application of local heating (LH) at acupoints. Objective: We used laser Doppler flowmetry (LDF) and spectrum analysis to investigate differences in the microcirculatory responses to the application of homogeneous LH at Hoku and two nearby nonacupoints. Methods: Thirty-four trials were performed on 10 male healthy volunteers. For each experiment, we recorded a 20-minute baseline data sequence, then applied LH by an infrared-radiation lamp and recorded another 20-minute heating-effect sequence. The relative energy contributions (RECs) for LDF periodic oscillations in five characteristic frequency regions from 0.0095 to 1.6 Hz (segmented into FR1–FR5) were calculated by wavelet analysis. Results: The flux increased significantly following LH. Decreases in RECs of FR2 and FR3, increases in RECs of FR1 and FR5, and the flux increase following LH were all largest at Hoku. Conclusion: Our results suggest that the application of LH to acupoints induces larger therapeutic effects. This might partly account for the physiological mechanism of moxibustion, and could contribute to optimizing the microcirculatory improvement by applying LH treatments. Frequency-band analysis appears to be a promising tool for studying microcirculatory responses induced by various TCM treatments.