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Journal of Luminescence 119–120 (2006) 96–99

www.elsevier.com/locate/jlumin

Photoluminescence of acupoint ‘‘Waiqiu’’ in humansuperficial fascia

Yuan Zhanga, Xiaohui Yana, Chenglin Liua, Ruishan Dangb, Xinyi Zhanga,c,�

aSynchrotron Radiation Research Center, Department of Physics, Surface Physics Laboratory (State Key Laboratory) of Fudan

University, Shanghai 200433, PR ChinabSecond Military Medical University, Shanghai 200433, PR China

cShanghai Research Center of Acupuncture and Meridian, Pudong, Shanghai 201203, PR China

Available online 15 February 2006

Abstract

The spectral characters of an acupuncture point named ‘‘Waiqiu’’ in superficial fascia tissue have been studied by

photoluminescence (PL) spectroscopy under the excitation of 457.9 nm. The PL around ‘‘Waiqiu’’ acupuncture point

consists of two sub-bands resulting from the flavin adenine dinucleotide (FAD) and phospholipids, and the porphyrins

(including purine, isoxanthopterin and tryptophan), respectively. More emission due to FAD and phospholipids is

found inside the acupuncture effect area of ‘‘Waiqiu’’ than its marginal or outside acupuncture regions. The ratio of

emission intensity of FAD and phospholipids to one of porphyrins gradually decreases along the direction away from

the center of the acupuncture point. It implies that the component proportion changes between FAD, phospholipids

and porphyrins around the ‘‘Waiqiu’’ acupuncture point. We suggest that there might be a certain relationship between

redox function of FAD and ‘‘Waiqiu’’ acupuncture effect.

r 2006 Elsevier B.V. All rights reserved.

Keywords: Photoluminescence; ‘‘Waiqiu’’ acupoint; Superficial fascia; FAD

1. Introduction

As we all know that the traditional Chineseacupuncture is a medical treasure in oriental culture

e front matter r 2006 Elsevier B.V. All rights reserve

min.2005.12.051

ing author. Synchrotron Radiation Research

ment of Physics, Surface Physics Laboratory

oratory) of Fudan University, Shanghai 200433,

: +86 21 65643522.

ess: xy-zhang@fudan.edu.cn (X. Zhang).

and currently it has also popularized in westerncountries owing to some distinctive merits such asgood curative effect for certain kinds of syndromes,small side-effect for patients and low cost. Longbefore two thousand years, doctors have knownvery well about the concept of acupuncture points(or abbreviated as acupoints). These points distri-bute regularly in whole human body along severalspecific longitudinal lines or pathways, which arenamed meridians or ‘‘Jingluo’’ in Chinese. As the

d.

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Fig. 1. Sketch of the ‘‘Waiqiu’’ acupoint; the location of

‘‘Waiqiu’’ and the superficial fascia tissue that we take as a

sample are shown by the arrows.

Y. Zhang et al. / Journal of Luminescence 119– 120 (2006) 96–99 97

acupoint is stimulated by a needle, i.e. acupunc-tured, the patient will perceive various feelingsincluding distent, tingling and aching. These kindsof feelings are totally called the needle sensation or‘‘Deqi’’ in Chinese. Doctors could accurately locatepositions of corresponding acupoints for oneparticular disease (sometimes to find the acupointsby feelings of ‘‘Deqi’’ of the patient) and then carryout operations, i.e. acupuncture. Innumerable pa-tients have got well by acupuncture. For one specificacupoint, the needle sensation begins at the skin andends in the periosteum or interosseous membrane,and the degree of needle sensation changes indifferent depths of the needle. According to theneedle sensation doctors and researchers have alsofound the anatomical structures of some acupoints[1,2]; therefore, we can say that the acupoints havethree-dimensional structures. Nevertheless, the me-chanism of the cure of diseases is still not wellknown. Even the structure and the composition ofthese acupoints are uncertainty. In recent years,some researchers using different methods probe thebasic compositions and the physiological mechan-ism of acupuncture [3]. X-ray fluorescence analysesmethods are mainly used to explore trace elementscharacteristic of acupoints. One kind of X-rayfluorescence methods, the proton-induced X-raysemission (PIXE) has been used, and the concentra-tion of calcium is always found high within theacupoints [4].

In this paper, we take ‘‘Waiqiu’’ acupoint insuperficial fascia of human crus as an example anduse the photoluminescence (PL) spectroscopy tocharacterize the acpoint in order to know thespectral and, hence, the compositional differencesbetween acupoint and outside acupoint regions.

2. Experimental

The ‘‘Waiqiu’’ acupoint locates in human crus,and its anatomic structures are from skin, hypo-derm, then superficial fascia and fascia profunda,through muscles and end in fibula periosteum. Weuse a superficial fascia tissue where the acupoint‘‘Waiqiu’’ is located as our sample. It is a relativelyshallow part of the ‘‘Waiqiu’’ acupoint, as shownin Fig. 1. This tissue was dissected from the dead

by a dissector in the Second Military MedicalUniversity in Shanghai. It has a dimension of80� 50� 0.5mm3 (L�W�T), approximately, inthe middle of which is the acupoint ‘‘Waiqiu’’.Normally, the effective area of an acupoint hasa diameter of about 3–5mm. We can only knowthe approximate position of the acupoint fromthe dissector; therefore, we detected the concentra-tion of Ca by PIXE in order to determine moreprecisely the position and the effective areaof ‘‘Waiqiu’’ in our specimen. This tissue waspreserved in a sanitary pledget with formalin.The sample surface is flat enough for relativeluminescence intensity comparisons. During thePL measurements the specimen was stuck to acontrollable sample stage, with which we can easilymeasure the PL from different positions at thesample. The PL spectra were carried out at theJobin Yvon’s spectrometer U1000. The CoherentInc.’s InnovaTM 70-5 argon ion laser was used asthe excitation source. In our experiments, excita-tions under 488.0 or 457.9 nm with a fixed powerof about 40mW were used. The beam size of theincident light is about 0.3mm. The OriginTM 7.0

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Y. Zhang et al. / Journal of Luminescence 119– 120 (2006) 96–9998

software was used to smooth the raw data and forother calculations.

0

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450 500 550 600 650 700

E

D

C B

A

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E

D

C

BA

Fig. 3. Photoluminescence spectra of the sample inside the

effective acupuncture area and its outside. Curves A, B, C, D

and E are measured from different positions indicated in the

upper-right circle. Positions A, B, C and D are in the effective

area of ‘‘Waiqiu’’ and E is outside the acupoint.

3. Results and discussion

The PL spectra near the center of ‘‘Waiqiu’’ areshown in Fig. 2, in which curves A and B representthe spectra obtained under the excitation of 457.9or 488.0 nm, respectively. The emission spectrumcorresponding to the excitation of 457.9 nm con-sists of two sub-bands peaked at about 525 and590 nm, respectively, as shown by curve A, whilethe 488.0 nm is used as the excitation light; thespectrum is of two sub-bands structure as well, butthe sub-band in the higher energy side is obviouslyweaker than the other one (see curve B in Fig. 2).The sub-band around 525 nm can be attributed tothe fluorescence of flavin adenine dinucleotide(FAD) and phospholipids (one kind of lipids). Onthe other hand, the sub-band peak at about590 nm might be attributed to the fluorescence ofporphyrins, including purine, isoxanthopterin andtryptophan [5,6].Our pre-designed sampling points were marked

with A, B, C, D and E, as shown in the inset ofFig. 3. These points are along the direction awayfrom the center of the acupoint to its marginalarea, and the point E is already outside theeffective region of the acupoint. The distancebetween points A and D is about 2.5mm. Fig. 3

460 480 500 520 540 560 580 600 620 640 660 680 700 720

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16000

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AB

Fig. 2. Photoluminescence spectra of ‘‘Waiqiu’’ acupoint with

the excitation of (A) 457.9 and (B) 488.0 nm respectively.

shows the PL spectra under the excitation of457.9 nm, and curves A, B, C, D and E correspondto spectra recorded at points A, B, C, D and E,respectively. It can be seen, obviously, that theratio between intensities of the two sub-bandsvaries gradually from spectrum A to spectrum E,as shown in Fig. 4. Consequently, we could cometo the conclusion that, compared to the porphyr-

0 1 2 3 540.6

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R (

a. u

.)

D (mm)

Fig. 4. Ratio of the emission intensity of FAD and phospho-

lipids to that of porphyrins (R) in different positions A, B, C, D

and E as a function of distance (D) away from point A.

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Y. Zhang et al. / Journal of Luminescence 119– 120 (2006) 96–99 99

ins, the concentration of FAD and phospholipidsdecreases relatively from the center of ‘‘Waiqiu’’ toits marginality, and is greatly decreased at positionE, outside of ‘‘Waiqiu’’. In other words, we believethat more FAD and phospholipids exist in theefficient acupoint regions. As we know, FAD isvirtually a kind of coenzyme which has a vitalfunction for oxygen removal during the processesof the oxidation–deoxidation reaction. Therefore,we could relate the ‘‘Waiqiu’’ acupoint to certainbiological redox functions, and suggest that theFAD’s function, the oxidation–deoxidation reac-tion, might be an important processes in acupunc-ture, which result in the special curative effects ofacupuncture at acupoints.

4. Conclusions

The PL at various positions of an acupoint‘‘Waiqiu’’ has been systematically studied. Theemission spectrum resulting from the superficialfascia tissue, in which the acupoint ‘‘Waiqiu’’ islocated, consists of two sub-bands peaked at 590and 525 nm, respectively. It is found that the PLdue to FAD and phospholipids decreases gradu-ally along the direction away from the centerof the acupoint. Considering the special effect of

FAD, i.e., the oxygen removal ability in oxida-tion–deoxidation reactions, it is not unreasonableto think there is relatively high concentration ofFAD in the acupoint ‘‘Waiqiu’’ and the redoxeffect might be important during the acupuncture.

Acknowledgments

This work was supported by National BasicResearch Program of China (no. 2005CB523306).We would like to thank Professor HuanshengChen of the Institute for Modern Physics at FudanUniversity for the PIXE measurements to deter-mine the acupoint’s range.

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