Assessing the microcirculatory response following oral administration of Liuwei Dihuang formula by spectral analysis of skin-surface laser Doppler signals.

OBJECTIVE

This study aimed to assess the skin-surface microcirculatory effects of oral administration of Liuwei Dihuang (LW) formula by analyzing the frequency content of laser-Doppler skin blood-flow signals at important acupoints.

METHODS

Laser-Doppler signals were measured in male healthy volunteers in two groups of experiments: the LW experiment (n=42; aged (27.8±3.8) years) and the control experiment (n=28; aged (27.3±3.4) years). Each experiment involved a 20-minute baseline-data sequence and three following sets of effects data: recorded on the same day after oral administration of 250 mL water (28 degrees centigrade) accompanied with 5 g of LW formula (herbal extract granules), and recorded on the second day after taking other two doses of LW formula.

RESULTS

During the second day, the increases in the mean and pulsatile components of the flux signal were the most prominent, and the relative energy contribution at 0.02 to 0.06 Hz was significantly decreased at Taixi (KI3). There were no any other significant changes in these parameters at other measurement sites.

CONCLUSION

The redistribution of skin-surface microcirculatory blood flow following oral LW administration observed here can be attributed to different changes in sympathetic neural activities and thus the different perfusion resistance through the arteriolar openings of the peripheral vascular beds at different measurement sites. The developed noninvasive and real-time monitoring technique could form part of an evidence-based method for studying the physiological effects and the underlying mechanisms of traditional Chinese medicine herbs.