Effects of chitosan and low level laser therapy, associated or not, in treatment of osteoarthritis induced in rat knee

Abstract

Osteoarthritis (OA) is a degenerative progressive disease characterized by loss of articular cartilage, subchondral bone remodelling, reduction of articular space and osteophytes formation, which leads to appearance of algic state and functional losses in affected individuals. Thus, it becomes essential the development of therapeutic strategies that aim to diminish the articular damage and to prevent disease's evolution. Currently, low level laser therapy (LLLT) and chitosan have shown positive effects on cartilage metabolism. Nevertheless, mechanism of action and association effects of both treatments still need enlightening. Thus, the objective of this study is to evaluate, through in vivo tests, effects of chitosan and LLLT (associated or not) on OA's experimental model, induced through anterior cruciate ligament transection (ACLT). This test will use 40 male Wistar rats, divided in four groups: control OA; OA treated with chitosan; OA treated with LLLT; OA treated with chitosan and LLLT. The treatments will begin 21 days after ACLT surgery and will last for 30 days. It will be used a laser AsGaAl 808 nm; P=50 mW; D=50 J/cm²; E=1.4 J, 3 times a week, in 2 points: knee's medial and lateral articular line. In order to evaluate and compare treatments effect, it will be performed cytokine analysis of tumour necrosis factor alpha (TNF-±), prostaglandin E2 (PGE2) and transforming growth factor beta (TGF-²) in synovial liquid and cartilage computed microtomography, morphological and morphometric analysis (cell number, thickness, chondrocytes density and proteoglycan content) and protein expression of interleukin (IL-1², IL-4 and IL-10) and type 2-alpha-1 collagen (col2A1). It is hoped the results of this project bring significant contributions in enlightening of chitosan and LLLT (and their association) mechanisms of action in an OA experimental model, leading to a development of more efficient and safe therapeutic technics to be employed in treatment of osteodegenerative diseases. (AU)