Acupuncture, the ancient Chinese therapy, has been found to significantly reduce levels of a protein linked to chronic stress.
Although the study was done in rats, researchers at Georgetown University Medical Center (GUMC) suggest the findings could help explain why many users of the therapy report health benefits.
The researchers say that if their findings were replicated in human studies, acupuncture would offer a proven therapy for stress, which is often difficult to treat.
"It has long been thought that acupuncture can reduce stress, but this is the first study to show molecular proof of this benefit," said the study's lead author, Ladan Eshkevari, Ph.D., an assistant professor at Georgetown's School of Nursing and Health Studies, a part of GUMC.
Eshkevari designed a study to test the effect of acupuncture on blood levels of neuropeptide Y (NPY), a peptide that is secreted by the sympathetic nervous system in humans.
This system is involved in the "flight or fight" response to acute stress, resulting in constriction of blood flow to all parts of the body except to the heart, lungs, and brain (the organs most needed to react to danger). Chronic stress, however, can cause elevated blood pressure and cardiac disease.
The study utilized four groups of rats for a 14-day experiment: a control group that was not stressed and received no acupuncture; a group that was stressed for an hour a day and did not receive acupuncture; a group that was stressed and received "sham" acupuncture near the tail; and the experimental group that were stressed and received acupuncture to the Zuslanli spot on the leg.
She found NPY levels in the experimental group came down almost to the level of the control group, while the rats that were stressed and not treated with Zuslanli acupuncture had high levels of the protein.
In a second experiment, Eshevari stopped acupuncture in the experimental group but continued to stress the rats for an additional four days, and found NPY levels remained low.
"We were surprised to find what looks to be a protective effect against stress," she noted.
The study has been published online in December in Experimental Biology and Medicine.