Laser acupuncture – fact or fiction?
By Jan Tunér
The application of laser instead of needles has a long history. The very low powered HeNe laser was used in the beginning of the 80ies and from that period different lasers have been widely used to replace needles. But does that really work? Possibly, but the first question should really be: Does acupuncture work?
The first thorough scientific evaluation of acupuncture was performed by the World Health Organization in 1979. The report was positive about a great number of medical indications. In 2003 the WHO published a less positive report, ”Acupuncture: Review and analysis of reports on controlled trials. 293 studies”. Later on, the Cochrane collaboration performed an analysis of the available literature, and came to a less optimistic conclusion. There was some evidence for a few indications, notably certain types of pain, nausea and vomiting, throat problems and nocturnal uresis. The number of scientifically accepted indications for acupuncture was shrinking.
Laser acupuncture was not mentioned in these reports, in spite of being performed in parallel with needling during 20 years. Using a laser instead of a needle appeared attractive; there was no pain involved and no risk of infection. The drawback was that the use of multiple points was not possible.
Critics pointed out the problems to understand and accept laser acupuncture. All wavelengths seemed to work and any power density and energy too. And when needling is used, it is important to pinpoint a very small acupuncture point and get the ”qi” reaction. When a laser is used, a very large area is illuminated and there is no qi. The problem is very obvious in auricular acupuncture. Using an infrared laser on 3-4 points in the ear means that the entire ear has been illuminated! It just does not make sense. Still, studies using fMRI [1,2] showed that the reactions in the brain were similar when using a needle and a laser. So obviously it workes, but how?
We may now have an explanation at hand! In 2009 Burnstock [3] proposed that mechanical deformation of the skin by needles and application of heat or electrical current leads to release of large amounts of ATP from keratinocytes, fibroblasts and other cells in skin; the ATP then occupies specific receptor subtypes expressed on sensory nerve endings in the skin and tongue; the sensory nerves send impulses through ganglia to the spinal cord, the brain stem, hypothalamus and higher centres; the brain stem and hypothalamus contain neurons that control autonomic functions, including cardiovascular, gastrointestinal, respiratory, urinogenital and musculo-skeletal activity. Impulses generated in sensory fibres in the skin connect with interneurons to modulate (either inhibition or facilitation) the activities of the motoneurons in the brain stem and hypothalamus to change autonomic functions; specifically activated sensory nerves, via interneurons, also inhibit the neural pathways to the pain centres in the cortex.
In 2012 Goldman [4] found that adenosine, a neuromodulator with anti-nociceptive properties, was released during acupuncture in mice and that its anti-nociceptive actions required adenosine A1 receptor expression. Direct injection of an adenosine A1 receptor agonist replicated the analgesic effect of acupuncture. Inhibition of enzymes involved in adenosine degradation potentiated the acupuncture-elicited increase in adenosine, as well as its anti-nociceptive effect. These observations indicate that adenosine mediates the effects of acupuncture and that interfering with adenosine metabolism may prolong the clinical benefit of acupuncture.
What implication does this has for laser acupuncture? Well, is has been known for more than 30 years that laser irradiation at certain energy levels triggers increased mitochondrial production of ATP [5-9]! And ADP is a precursor to ATP. This possible explanation has been put forward by Karu [10]. So if the stimulation of ADP/ATP is the basic mechanism of needling and laser acupuncture, then the confusion may be over.
The laser acupuncture technique has been refined by the introduction of ”laser needles”. These are very thin fibres which stick to the area over the acupuncture point by an adhesive ring. Several points can be irradiated at the same time and different wavelengths can be selected. The thin fibres can introduce the photons over small areas and the use of e.g. green light can reduce the scattering of the light, thus making auricular therapy more feasible.
Photo: Weber Medical
A few recent clinical studies [11-13] are included in the list of references below.
References
[1] Siedentopf C M, Golaszewski S M, Mottaghy F M, Ruff C C, Felber S, Schlager A. Functional magnetic resonance imaging detects activation of the visual association cortex during laser acupuncture of the foot in humans. Neurosci Lett. 2002; 327 (1): 53-56.
[2] Litscher G, Rachbauer D, Ropele S, Wang L, Schikora D, Fazekas F, Ebner F. Acupuncture using laser needles modulates brain function: first evidence from functional transcranial Doppler sonography and functional magnetic resonance imaging. Lasers Med Sci. 2004; 19 (1): 6-11.
[3] Burnstock G. Acupuncture: a novel hypothesis for the involvement of purinergic signalling. Med Hypotheses. 2009; 73 (4): 470-472.
[4] Goldman N, Chen M, Fujita T, Xu Q, Peng W, Liu W, Jensen TK, Pei Y, Wang F, HanX, Chen JF, Schnermann J, Takano T, Bekar L, Tieu K, Nedergaard M. Adenosine A1 receptors mediate local anti-nociceptive effects of acupuncture. Nat Neurosci. 2010; 13 (7): 883-888.
[5] Salet C, Moreno G, Vinzens F. A study of beating frequency of a single myocardial cell. III. Laser microirradiation of mitochondria in the presence of KCN or ATP. Exp. Cell Res. 1979; 120: 25.
[6] Passarella S et al. Increase in the ADP/ATP exchange in rat liver mitochondria irradiated in vitro by helium-neon laser. Biochem Biophys Res Commun. 1988; 156 (2): 978-986.
[7] Pastore D et al. Stimulation of ATP synthesis via oxidative phosphorylation in weak mitochondria irradiated with helium-neon laser. Biochem Mol Biol Int. 1996; 39 (1): 149-157.
[8] Karu T, Pyatibrat L, Kalendo G. Irradiation with He-Ne laser increases ATP level in cells cultivated in vitro. J Photochem Photobiol B. 1995; 27 (3): 219-223.
[9] Houreld NN, Masha RT, Abrahamse H. Low-intensity laser irradiation at 660 nm stimulates cytochrome c oxidase in stressed fibroblast cells. Lasers Surg Med. 2012; 44 (5): 429-434.
[10] Karu T I. Mitochondrial Mechanisms of Photobiomodulation in Context of New Data About Multiple Roles of ATP. Photomed Laser Surg. 2010; 28 (2): 159-160.
[11] Chow R, Yan W, Armati P. Electrophysiological effects of single point transcutaneous 650 and 808 nm laser irradiation of rat sciatic nerve: a study of relevance for low-level laser therapy and laser acupuncture. Photomed Laser Surg. 2012; 30 (9): 530-535.
[12] Shin YI, Kim NG, Park KJ, Kim DW, Hong GY, Shin BC.Skin adhesive low-level light therapy for dysmenorrhoea: a randomized, double-blind, placebo-controlled, pilot trial. Arch Gynecol Obstet. 2012; 286 (4): 947-952.
[13] Cunha RG, Rodrigues KC, Salvador M, Zangaro RA. Effectiveness of Laser treatment at acupuncture sites compared to traditional acupuncture in the treatment of peripheral artery disease. Conf Proc IEEE Eng Med Biol Soc. 2010; 1262-1265. doi: 10.1109/IEMBS.2010.5626418.