Photobiological mechanism of light-emitting diode therapy in neuropathic pain induced in mice

• Grant number: 16/13941-6
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: January 01, 2017
• End date: February 29, 2020
• Field of knowledge: Health Sciences - Physiotherapy and Occupational Therapy
• Principal Investigator: Nivaldo Antonio Parizotto
• Grantee: Glauce Regina Pigatto
• Host Institution: Universidade de Araraquara (UNIARA). Associação São Bento de Ensino. Araraquara , SP, Brazil

Abstract

Neuropathic pain that originates as a result of injury of spinal nerves is characterized by an abnormal response of the transmission pathways of pain. In addition, changes generated by muscle denervation impair motor function, which along with neuropathic pain decrease the quality of patient's life. LEDT (Light Emitting Diode Therapy) is a very recent category of phototherapy. Scientific evidences show that LEDT accelerate nerve regeneration, in addition to reducing inflammation and pain. However, there are few scientific studies about the mechanism of action of LEDT in pain control, especially with regard to neuropathic pain. Therefore, the aim of this work is to study the antinociceptive and neuroregenerative effects of LEDT through acute and chronic nociception models, as well as investigate the possible underlying mechanism to this effect. Adult male Swiss mice (25 to 35 g) with age approximately of 2 months will be used for the realisation of the experiments. Several models of nociception will be carried out, among them: formalin-induced nociception, cinnamaldehyde, forbol myristate acetate (PMA), forscolina, nociception induced by intrathecal administration of excitatory aminoacids and pro-inflammatory cytokines TNF-± and IL-1². Model of chronic pain will be trough chronic constriction of sciatic nerve (ICC) and 7 days after the injury, mice will be submitted to the treatment with LEDT (890 nm, 390 mW, 20.8 J/cm ², 20 min) during 2 months, with applications 3 times a week. Nociceptive and behavioral tests will be carried out prior to injury, 7 days post injury and repeated every 7 days. Animals will be divided into 4 groups: sham animals (without injury and with treatment LEDT), animals (sham without injury and without treatment with LEDT), animals with ICC without treatment with LEDT and animals with ICC and treated with the LEDT. The possible activation of serotonergic and gabaergic systems, inhibition of pro-inflammatory cytokines and activation of anti-inflammatory cytokines will be also analyzed. Ex vivo investigations will be performed by biochemical, immunological and imunohistological analysis for verification of efficiency of therapy in the control of neuropathic pain. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

PIGATTO, GLAUCE REGINA; SILVA, CAROLINA SEABRA; PARIZOTTO, NIVALDO ANTONIO. Photobiomodulation therapy reduces acute pain and inflammation in mice. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY, v. 196, JUL 2019. (16/13941-6)

PIGATTO, GLAUCE R.; QUINTEIRO, MAIARA H. S.; NUNES-DE-SOUZA, RICARDO L.; COIMBRA, NORBERTO C.; PARIZOTTO, NIVALDO A.. Low-Intensity Photobiomodulation Decreases Neuropathic Pain in Paw Ischemia-Reperfusion and Spared Nervus Ischiadicus Injury Experimental Models. PAIN PRACTICE, v. 20, n. 4, DEC 2019. (17/11855-8, 16/13941-6)