RESUMO
The purpose of this study is to evaluate the effects of photobiomodulation (PBM) therapy in chondrocyte response by in vitro experiments and cartilage repair using an experimental model of osteoarthritis (OA) in the knee of rats. The in vitro experiment was performed with chondrocyte cells, and they were divided into two groups: non-irradiated and irradiated with PBM (808 nm; 0.8 J or 1.4 J). Then, cell proliferation was evaluated after 1, 3, and 5 days. The experimental model of osteoarthritis (OA) was performed in the knee of 64 Wistar rats, and they were assorted into control group (CG), PBM (808 nm; 1.4 J). The results of in vitro showed that PBM 1.4 J increased cell proliferation, on days 1 and 5. However, after 3 days was demonstrated a significant increase in cell proliferation in PBM 0.8 J. The in vivo experiment results demonstrated, on histological analysis, that PBM presented less intense signs of tissue degradation with an initial surface discontinuity at the superficial zone and disorganization of the chondrocytes in the cartilage region when compared to CG, after 4 and 8 weeks. These findings were confirmed by immunohistochemistry and qRT-PCR analysis which showed that PBM increased IL-4, IL-10, COL-2, Aggrecan, and TGF-ß which are anabolic factors and acts on extracellular matrix. Also, PBM reduces the IL1-ß, an inflammatory marker that operates as a catabolic factor on articular cartilage. In conclusion, these results suggest that PBM may have led to a return to tissue homeostasis, promoting chondroprotective effects and stimulating the components of the articular tissue.
Assuntos
Cartilagem Articular , Terapia com Luz de Baixa Intensidade , Osteoartrite do Joelho , Osteoartrite , Animais , Cartilagem Articular/patologia , Condrócitos/patologia , Modelos Animais de Doenças , Osteoartrite/genética , Osteoartrite/metabolismo , Osteoartrite/radioterapia , Osteoartrite do Joelho/genética , Osteoartrite do Joelho/radioterapia , Ratos , Ratos WistarRESUMO
The aim of this study was to evaluate the effects of laser phototherapy on the degenerative modifications on the articular cartilage after the anterior cruciate ligament transection (ACLT) in the knee of rats. Eighty male rats (Wistar) were distributed into four groups: intact control group (IG), 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). Animals were distributed into two subgroups, sacrificed in 5 and 8 weeks postsurgery. The ACLT was used to induce knee osteoarthritis in rats. After 2 weeks postsurgery, laser phototherapy initiated and it was performed for 15 and 30 sessions. The histological findings revealed that laser irradiation, especially at 10 J/cm(2), modulated the progression of the degenerative process, showing a better cartilage structure and lower number of condrocytes compared to the other groups. Laser phototherapy was not able to decrease the degenerative process measured by Mankin score and prevent the increase of cartilage thickness related to the degenerative process. Moreover, it did not have any effect in the biomodulation of the expression of markers IL1ß, tumor necrosis factor-α, and metalloprotein-13. Furthermore, laser irradiated animals, at 50 J/cm(2) showed a lower amount of collagen type 1.
