Laser acupuncture for acute inflammatory, visceral and neuropathic pain relief: An experimental study in the laboratory rat

Abstract

Laser acupuncture is defined as the stimulation of traditional acupuncture points with low-intensity, non-thermal laser irradiation. We explored the clinical efficacy of a very low level diode laser wavelength 670 nm (Biolite LP020, RGM, Genoa, Italy), used to stimulate acupoints ST36 Zu San Li and TH5 Waiguan, on well-established experimental models of acute and persistent pain in the rat, e.g. acute inflammatory pain, muscle pain, visceral pain and neuropathic pain. We report the anti-edema and anti-hyperalgesia effects of laser acupuncture in models of acute inflammatory pain, e.g. CFA-induced inflammation and myofascial pain. We also indicate that spontaneous pain and thermal hyperalgesia are reduced in a neuropathic pain model, e.g. axotomy. On the contrary, no effects due to laser-acupuncture were observed on discomfort indices in a model of visceral pain, e.g. cystitis due to cyclophosphamide. We thus provide evidences that acupoints stimulation using a very low intensity laser irradiation can control pain and edema in specific experimental conditions.