A certain acupuncture technique may be effective for relieving pain, while others may not be so successful.
But does it work? Previous studies have produced mixed results, and clinical guidelines for the use of acupuncture are conflicting.
A new study - published in the journal Evidence-based Complementary and Alternative Medicine - examines some of the reasons behind why previous research may have deemed acupuncture controversial.
The new research was carried out by a team of scientists from the biomedical research institute LA BioMed, and the study's corresponding author is LA BioMed's lead researcher Dr. Sheng-Xing Ma.
Studying the effects of acupuncture
The novelty of the research conducted by Dr. Ma and colleagues consists of a device that allowed the researchers to take samples of human molecules from the skin, therefore enabling them to study the effect of needling.
"Our lab has developed a painless, non-invasive biocapture device that can sample human biomolecules over specific skin regions. With this tool, we were able to obtain the first evidence that nitric oxide is released from the human skin surface at a higher level with the proper acupuncture methodology and the use of heat."
Dr. Sheng-Xing Ma
Dr. Ma and team used a "low-force/rate" method of manual acupuncture, during which they inserted acupuncture needles gently into the skin of 25 male and female participants, aged between 18 and 60, for 20 minutes.
The needles were twisted every 5 minutes throughout the 20-minute period. The researchers delicately twisted the needles according to the standard reinforcement procedure for 2 minutes, or until the "de qi sensation" - that is, a "feeling of soreness, numbness, distension, or pain" - was achieved.
The researchers wanted to examine the effect of needling on the release of nitric oxide on the skin. They taped the biocapture device, together with collecting solution, to the skin of the participants, covering the two pathways, or meridians, along which important bodily energy is said to flow: the pericardium and the lung.
Acupuncture technique raises nitric oxide
Dr. Ma and colleagues also applied electrical heat of around 43 to 44°C for 20 minutes, and they carried out two 20-minute biocapture sessions "during and after each treatment."
The experiment revealed high levels of nitric oxide at the acupoints defined along the two meridians.
The authors explain that nitric oxide increased the blood flow, which, in turn, may have triggered the release of analgesic substances that make the skin feel warm and enhance the therapeutic effect of needling.
However, "the precise mechanisms of the elevation of [nitric oxide] release affected by the stimulations applied are still unclear," admit the researchers. "A more sophisticated approach would be required to address this issue."
To test their findings further, Dr. Ma and team also applied a "reduction method," in which they administered the needles with high force and high frequency.
"Based on traditional Chinese medicine, acupuncture reinforcement is attained by slowly twisting or rotating the needle with gentle force or by heat," Dr. Ma explains. "Reduction is attained by rapidly twisting or rotating the needle with great force. Reinforcement results in [a] local feeling of warmness, but reduction causes a local feeling of coldness."
Under reduction conditions, nitric oxide levels decreased. The difference between these two methods may account for the varying results found in acupuncture trials, the authors suggest.
They also mention that they will keep examining the differences between these methods of manual acupuncture in order to understand how effective each of them is for relieving pain, as well as for grasping the biomolecular mechanisms involved in pain reduction.