The Role of Acupuncture on the Gut–Brain–Microbiota Axis in Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a chronic dysfunction of the gastrointestinal tract, commonly characterized by abdominal pain or abdominal discomfort. These symptoms can substantially reduce the quality of life and work productivity of the patients. The exact pathogenesis of IBS remains unclear, as it has become apparent that multiple pathways are activated in the condition, including inflammation, immunology, neurology and psychology. Recent evidence has shown that symptoms in IBS are related to the dysfunction of the nervous system, particularly the viscerosomatic pathway, through immune-to-brain communication. The potential link between brain–gut relationships is gut microbiota. The management of IBS mostly focuses on symptomatically treating the patients. There are a wide range of standard treatments, including pharmacological to psychological interventions which are effective in some patients. Therefore, a combination of therapies including both standard and complimentary treatments, including Traditional Chinese Medicine (TCM) such as acupuncture, have been used in treating IBS patients. Several in vivo and clinical studies have demonstrated the efficacy of acupuncture in treating IBS. Increasing attention has been paid to research regarding the action mechanisms of acupuncture for IBS. This paper summarizes and discusses the possible mechanisms associated with acupuncture on the pathophysiology of IBS, including gastrointestinal (GI) motility, visceral hypersensitivity, the immune system, neurotransmitters, and the brain–gut axis. The results fromin vivo and clinical studies have been included. In addition, the effects of acupuncture on gut microbiota in IBS are included and any contradictory findings are deliberated.