Specificity of auricular acupoints in reflecting changes of qi and blood measured by diffuse reflectance spectroscopy

OBJECTIVE: This study aimed to assess the specificity of auricular acupoints in responding to changes of qi and blood which, in traditional Chinese medicine, are considered as the fundamental substances in the human body for sustaining normal vital activity.METHODS: A miniature fiber optic system was used to invasively measure the diffuse reflectance spectra of three auricular acupoints, namely, Uterus (TF2), Gan (CO12) and Neifenmi (CO18), at different stages of menstruation, when the female body exhibits regular changes of qi and blood. The spectra of different acupoints were compared to find their difference in responding changes of qi and blood, especially the reflectivity of absorption peaks of hemoglobin.RESULTS: The reflectivity of the same auricular acupoint during menstruation is higher than that before and after menstruation, and this trend is more obvious for the Uterus point compared with the points Gan and Neifenmi. The average reflectivity of the Uterus point during menstruation was significantly higher than that before or after menstruation (P＜0.01). The D-values during and after menstruation of the Uterus point were greater than those of the points Gan and Neifenmi at 544.06 and 577.47 nm, respectively (P＜0.05).CONCLUSION: The diffuse reflectance light of auricular acupoints changes as qi and blood fluctuates, and there is relative specificity among different auricular acupoints in reflecting changes of qi and blood. The Uterus point may be the most sensitive auricular acupoint in reflecting uterus function and subsequent changes of qi and blood.