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Effects of resistance exercise therapy and low intensity laser on the quadriceps muscle of rats with osteoarthritis induced by transection of the anterior cruciate ligament

Grant number: 14/17735-6
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): October 01, 2014
Effective date (End): September 30, 2016
Field of knowledge:Health Sciences - Physiotherapy and Occupational Therapy
Principal Investigator:Ana Claudia Muniz Renno
Grantee:Heloisa de Sousa Domingos
Home Institution: Instituto de Saúde e Sociedade (ISS). Universidade Federal de São Paulo (UNIFESP). Campus Baixada Santista. Santos , SP, Brazil

Abstract

Osteoarthritis of the knee is a chronic musculoskeletal disease, and as a major consequence of the atrophy and weakness of periarticular muscles that cause significant functional limitation of the affected patient. Exercise therapy and low intensity laser (LLLT) are therapeutic strategies that assist in the reduction of musculoskeletal abnormalities resulting from AO knee, however the mechanisms activated by these resources remain uncertain. The objective of this study is to evaluate the effects of resistance exercise associated with LLLT on the quadriceps muscle of rats subjected to an experimental model of OA induced by section of the anterior cruciate ligament (ACLT). Will be used 40 Wistar rats, males, divided into 5 groups (n = 8): control (CG); osteoarthritic (GO); osteoarthritic and resistance exercise (Goer); osteoarthritic irradiated with LLLT (GOL); osteoarthritic resistance exercise and irradiated with LLLT (GOERL). Treatments will begin four weeks after surgery. The resistance exercise protocol consist of jumps in liquid medium at 32 ° C: 4 sets of 10 jumps each, with intervals of 30 seconds between sets 3 days a week for 8 weeks, with loads ranging from 50-70% of body mass of the animal. A laser it will be used AsGaAl (continuous, » = 808 nm, P = 50 mW, beam area = 0.028 cm2, t = 28 s, D = 50 J/cm2, E = 1.4 J; irradiance = 17.8 mW GaAlAs a laser (continuous is used / cm2), 3 times per week and / or after training sessions at 2 points of the left hind leg (medial and lateral joint line).To assessment and comparisons of effects of treatment will be executed analyzes of cross-sectional area of muscle fibers (AST) of the vastus medialis and the immunoreactivity of MURF-1 and atrogin-1. It is expected that the results of this project will bring significant contribution in elucidating the mechanisms of action triggered by exercise, LLLT and combination of both for atrophy and muscle weakness present in knee OA, thus optimizing the use of safe and effective resources for rehabilitation of degenerative disorders. (AU)