ABSTRACT
ObjectiveTo investigate the effects of Tongluo Juanbi granules on chondrocyte apoptosis and Toll-like receptor 4 （TLR4）/myeloid differentiation factor 88 （MyD88）/nuclear factor-κB （NF-κB） signaling pathway of rabbits with knee osteoarthritis （KOA） and study the mechanism of Tongluo Juanbi granules in the prevention and treatment of KOA. MethodThirty New Zealand rabbits were randomly assigned to the following five groups （n=6）： sham group， model group， low-dose and high-dose groups of Tongluo Juanbi granules （4.1 and 8.2 g·kg-1·d-1）， and celecoxib group （10.9 mg·kg-1·d-1）. The KOA model was established by destabilization of the medial meniscus （DMM） for six weeks. Six weeks after the modeling， the drug was given once a day for eight weeks. The pathological changes of cartilago articularis were observed by hematoxylin-eosin （HE） staining and Safranin O-Fast Green staining. Terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL） staining was performed to detect chondrocyte apoptosis. Enzyme-linked immunosorbent assay （ELISA） was used to detect the contents of interleukin-1β （IL-1β） and tumor necrosis factor-α （TNF-α） in synovial fluid. The mRNA and protein expression levels of genes related to the TLR4/MyD88/NF-κB signaling pathway were detected by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot， respectively. ResultCompared with the sham group， the cartilago articularis of the model group significantly degenerated. Mankin's score was increased （P<0.01）， and the contents of IL-1β and TNF-α in synovial fluid were increased （P<0.01）. The number of apoptosis of chondrocytes was increased （P<0.01）. The mRNA and protein expressions of TLR4， MyD88， and NF-κB p65 in cartilage tissue were up-regulated （P<0.01）， while the mRNA and protein expressions of Bcl-2 were down-regulated （P<0.01）. Compared with the model group， chondrocyte degeneration in both low-dose and high-dose groups of Tongluo Juanbi granules was improved， and Mankin's score was decreased （P<0.01）. The contents of IL-1β and TNF-α were decreased （P<0.01）， and the number of apoptosis of chondrocytes was decreased （P<0.01）. The mRNA and protein expressions of TLR4， MyD88， and NF-κB p65 in cartilage tissue were down-regulated （P<0.01）， while the mRNA and protein expressions of Bcl-2 were up-regulated （P<0.01）. In addition， in the above observation indicators， the high-dose group of Tongluo Juanbi granules was significantly superior to the low-dose group of Tongluo Juanbi granules. ConclusionTongluo Juanbi granules could inhibit chondrocyte apoptosis in rabbits with KOA and improve cartilage degeneration， which may be related to inhibiting inflammatory responses mediated by TLR4/MyD88/NF-κB signaling pathway.