Long derided by much of the mainstream medical community, acupuncture may have just got a little bit less alternative.
Despite thousands of years of anecdotal evidence claiming benefits in treating ailments from allergies to hiccups, acupuncture faces two big challenges to acceptance in mainstream medicine: most clinical trials have found no evidence of efficacy; and there is no scientifically accepted mechanism for how the treatment could work. Many researchers assume that any benefits are down to the placebo effect.
Now, research in mice has provided a biochemical explanation that some experts find more persuasive, although it might account for only some of the treatment’s supposed benefits. “Our study shows there is a clear biological mechanism behind acupuncture,” says Maiken Nedergaard, a neuroscientist at the University of Rochester, New York, who led the research, published in Nature Neuroscience.
Nedergaard’s team were interested in finding out whether the neuromodulator adenosine, which is produced on tissue injury and has pain-dulling properties, was involved in the pain-relieving effects of acupuncture.
After inducing chronic pain in the right legs of their mice, the researchers inserted and rotated an acupuncture needle just below the ‘knee’, at a point known in humans as the ‘Zusanli point’. For about an hour after the treatment, the mice took longer to respond to touch or heat on the paw, ultram.
The scientists found that the needle had caused tissue damage; they also noted an increase in local levels of a number of biologically active molecules, including adenosine.
Mice lacking a key receptor for adenosine did not show the same response after acupuncture.
Edzard Ernst, who studies the effectiveness of alternative therapies at the Peninsula Medical School in Exeter, UK, says that the mechanism is credible. But the work does not address whether acupuncture is actually an effective treatment, he adds. “If the clinical effect is not beyond placebo, which most of the well controlled clinical trials seem to suggest, the mechanism is irrelevant and the true mechanism is placebo,” he says.
Posted on behalf of Dan Cressey