Effectiveness of an aquatic exercise program and low-level laser therapy on articular cartilage in an experimental model of osteoarthritis in rats.

OBJECTIVE: The aim of this study was to evaluate the effects of an aquatic exercise program and low-level laser therapy (LLLT) (associated or not) on degenerative modifications and inflammatory mediators on the articular cartilage using an experimental model of knee OA. METHOD: Forty male Wistar rats were divided into 4 groups: knee OA - without treatment (OA); OA plus exercise program group (OAE); OA plus LLLT (OAL); OA plus exercise program associated with LLLT (OAEL). Trained rats performed a water-jumping program carrying a load equivalent to 50-80 % of their body mass strapped to their chest. The laser irradiation was used either as the only method or after the exercise training had been performed, at 2 points contact mode (medial and lateral side of the left joint). The treatments started 4 weeks after the surgery, 3 days/week for 8 weeks. RESULTS: The results revealed that all treated groups (irradiated or not) exhibited a better pattern of tissue organization, with less fibrillation and irregularities along the articular surface and improved chondrocytes organization. Also, a lower cellular density and structural damage (OARSI score) and higher thickness values were observed in all treated groups. Additionally, OAE and OAEL showed a reduced expression in IL-1ß and caspase-3 as compared with OA. Furthermore, a statistically lower MMP-13 expression was only observed in OAEL as compared with OA. CONCLUSION: These results suggest that aquatic exercise program and LLLT were effective in preventing cartilage degeneration. Also, physical exercise program presented anti-inflammatory effects in the knees in OA rats.

Low-level laser therapy prevents degenerative morphological changes in an experimental model of anterior cruciate ligament transection in rats.

The aim of this study was to analyze the effects of low-level laser therapy (LLLT) on the prevention of cartilage damage after the anterior cruciate ligament transection (ACLT) in knees of rats. Thirty male rats (Wistar) were distributed into three groups (n = 10 each): injured control group (CG); injured laser-treated group at 10 J/cm(2) (L10), and injured laser-treated group at 50 J/cm(2) (L50). Laser treatment started immediately after the surgery and it was performed for 15 sessions. An 808 nm laser, at 10 and 50 J/cm(2), was used. To evaluate the effects of LLLT, the qualitative and semi-quantitative histological, morphometric, and immunohistochemistry analysis were performed. Initial signs of tissue degradation were observed in CG. Interestingly, laser-treated animals presented a better tissue organization, especially at the fluence of 10 J/cm(2). Furthermore, laser phototherapy was able of modulating some of the aspects related to the degenerative process, such as the prevention of proteoglycans loss and the increase in cartilage area. However, LLLT was not able of modulating chondrocytes proliferation and the immunoexpression of markers related to inflammatory process (IL-1 and MMP-13). This study showed that 808 nm laser, at both fluences, prevented features related to the articular degenerative process in the knees of rats after ACLT.

Musculoskeletal Atrophy in an Experimental Model of Knee Osteoarthritis: The Effects of Exercise Training and Low-Level Laser Therapy.

OBJECTIVE: The aim of this study was to evaluate the effects of an exercise training protocol and low-level laser therapy (and the association of both treatments) on musculoskeletal atrophy using an experimental model of knee osteoarthritis (OA). DESIGN: Fifty male Wistar rats were randomly divided into five groups: control group, knee OA control group, OA plus exercise training group, OA plus low-level laser therapy group, and OA plus exercise training associated with low-level laser therapy group. The exercise training and the laser irradiation started 4 wks after the surgery, 3 days per week for 8 wks. The exercise was performed at a speed of 16 m/min, 3 days per week, 50 mins per day, for 8 wks. Laser irradiation was applied at two points of the left knee joint (medial and lateral), for 24 sessions. RESULTS: The results showed that both trained groups (irradiated or not) presented a significant increase in the muscle cross-sectional area and a decrease in muscle fiber density compared with the knee OA control group. Moreover, both trained and laser-irradiated groups demonstrated decreased muscle-specific ring-finger protein 1 and atrogin-1 immunoexpression. CONCLUSIONS: These results suggest that exercise training and low-level laser therapy were effective in preventing musculoskeletal alterations related to atrophy caused by the degenerative process induced by knee OA.