%0 Journal Article %T Effects of Low-Level Laser Therapy, 660£¿nm, in Experimental Septic Arthritis %A Bruna Forment£¿o Araujo %A L¨ªgia Inez Silva %A Anamaria Meireles %A Camila Thieimi Rosa %A Nereida Mello da Rosa Gioppo %A Alex Sandro Jorge %A Regina In¨ºs Kunz %A Lucin¨¦ia de F¨¢tima Chasko Ribeiro %A Rose Meire Costa Brancalh£¿o %A Gladson Ricardo Flor Bertolini %J ISRN Rheumatology %D 2013 %R 10.1155/2013/341832 %X The effectiveness of low-level laser therapy (LLLT) in the presence of an infectious process has not been well elucidated. The aim of the study was to evaluate the effects of LLLT in an experimental model of septic arthritis. Methods. Twenty-one Wistar rats were divided as follows: control group, no bacteria; placebo group, bacteria were inoculated; Treated group, bacteria were injected and treatment with LLLTwas performed. To assess nociception, a von Frey digital analgesimeter was applied. Synovial fluid was streaked to analyze bacterial growth. The standard strain of S. aureus was inoculated in the right knee. LLLT was performed with 660£¿nm, 2£¿J/cm2, over 10 days. After treatment, the knees were fixed and processed for morphological analysis by light microscopy. Results. It was found that nociception increases in the right knee. There was a lack of results for the seeding of the synovial fluid. The morphological analysis showed slight recovery areas in the articular cartilage and synovia; however, there was the maintenance of the inflammatory infiltrate. Conclusion. The parameters used were not effective in the nociception reduction, even with the slight tissue recovery due to the maintenance of inflammatory infiltrate, but produced no change in the natural history of resolution of the infectious process. 1. Introduction Septic arthritis is defined as bacterial invasion of the synovial space, and the knee is the most commonly affected joint in adults [1]. Also, the most frequent etiologic agent is Staphylococcus aureus. Joints are affected in several ways, such as hematogenous dissemination, penetrating trauma, contamination during surgical procedures, outbreaks of osteomyelitis, or abscess. Because it is an infectious process, it presents the classic signs of inflammation (pain, heat, swelling, and decreased range of motion), as well as fever and malaise [2]. Its treatment is difficult because it relies on the use of antibiotics, which have low penetration in the joint space [3], what would justify the use of an alternative therapy. The effectiveness of laser therapy in inflammatory signals has been demonstrated in a variety of experimental models. This physical feature has helped in controlling chemical mediators that play an important role in generating the inflammatory process, such as reduced expression of COX-2 [4], decrease in concentration of prostaglandin E2 (PGE2) [5], analgesia by the peripheral release of endogenous opioids [6], and edema reduction and anti-inflammatory action probably due to the release of adrenal hormones [7]. However, %U http://www.hindawi.com/journals/isrn.rheumatology/2013/341832/