Infrared (810-nm) low-level laser therapy on rat experimental knee inflammation

Author(s)

Pallotta, Rodney Capp ^[1] ; Bjordal, Jan Magnus ^[2] ; Frigo, Lucio ^[3] ; Pinto Leal Junior, Ernesto Cesar ^[4] ; Teixeira, Simone ^[1] ; Marcos, Rodrigo Labat ^[1] ; Ramos, Luciano ^[1] ; Messias, Felipe de Moura ^[4] ; Brandao Lopes-Martins, Rodrigo Alvaro ^{[1, 5, 4]}

Affiliation

^[1] Univ Sao Paulo, Lab Pharmacol & Expt Therapeut, Dept Pharmacol, Inst Biomed Sci, BR-05508900 Sao Paulo - Brazil

^[2] Bergen Univ Coll, Sect Evidence Based Res, Bergen - Norway

^[3] Univ Cruzeiro Sul, Biol Sci & Hlth Ctr, BR-08060070 Sao Paulo - Brazil

^[4] Nove Julho Univ, Post Grad Program Rehabil Sci, Sao Paulo - Brazil

^[5] Univ Sao Paulo, Lab Pharmacol & Phototherapy Inflammat, Dept Pharmacol, Inst Biomed Sci, BR-05508900 Sao Paulo - Brazil

• Document type: Journal article
• Source: Lasers in Medical Science; v. 27, n. 1, p. 71-78, JAN 2012.
• Web of Science Citations: 66

Abstract

Arthritis of the knee is the most common type of joint inflammatory disorder and it is associated with pain and inflammation of the joint capsule. Few studies address the effects of the 810-nm laser in such conditions. Here we investigated the effects of low-level laser therapy (LLLT; infrared, 810-nm) in experimentally induced rat knee inflammation. Thirty male Wistar rats (230-250 g) were anesthetized and injected with carrageenan by an intra-articular route. After 6 and 12 h, all animals were killed by CO(2) inhalation and the articular cavity was washed for cellular and biochemical analysis. Articular tissue was carefully removed for real-time PCR analysis in order to evaluate COX-1 and COX-2 expression. LLLT was able to significantly inhibit the total number of leukocytes, as well as the myeloperoxidase activity with 1, 3, and 6 J (Joules) of energy. This result was corroborated by cell counting showing the reduction of polymorphonuclear cells at the inflammatory site. Vascular extravasation was significantly inhibited at the higher dose of energy of 10 J. Both COX-1 and 2 gene expression were significantly enhanced by laser irradiation while PGE(2) production was inhibited. Low-level laser therapy operating at 810 nm markedly reduced inflammatory signs of inflammation but increased COX-1 and 2 gene expression. Further studies are necessary to investigate the possible production of antiinflammatory mediators by COX enzymes induced by laser irradiation in knee inflammation. (AU)

• FAPESP's process: 05/02117-6 - Effect of therapies of inhaled nitric oxide and low power laser on the experimental model fo tendonitis induced by collagenase in rats
• Grantee: Rodrigo Alvaro Brandão Lopes Martins
• Support Opportunities: Regular Research Grants