Abstract: BACKGROUND: Preliminary studies have found that massage therapy can alleviate damage to cartilage tissue, reduce inflammation, and inhibit chondrocyte apoptosis in knee osteoarthritis.
OBJECTIVE: To observe the effects of acupoint-pressing and knee-regulating therapy on the morphological structure of articular cartilage and inflammatory levels in rats with knee osteoarthritis. 
METHODS: Thirty-two Sprague-Dawley rats were randomly divided into a blank group, a model group, a medication group, and a massage group, with eight rats in each group. Rats in the model, medication, and massage groups were subjected to intra-articular injection of a mixture of papain and L-cysteine into the right knee joint (on days 1, 4, and 7) to establish a rat model of knee osteoarthritis. After modeling, the massage group received acupoint-pressing and knee-regulating therapy, while the medication group was treated with celecoxib via gavage. The remaining two groups received intraperitoneal injection of saline solution, once daily, for continuous 2 weeks. The diameter of the right knee joint, range of motion, and the paw withdrawal threshold were recorded. ELISA was used to detect serum levels of interleukin-6, interleukin-18, tumor necrosis factor-α, and matrix metallopeptidase 1. Hematoxylin-eosin staining was used to observe the degree of cartilage degeneration.
RESULTS AND CONCLUSION: (1) The knee joint diameter in the model group was greater than that in the blank group (P < 0.05), while knee joint range of motion and paw withdrawal threshold were lower than those in the blank group (P < 0.05). In the massage and medication groups, the knee joint diameter was smaller than that in the model group (P < 0.05), while knee joint range of motion and paw withdrawal threshold were higher than those in the model group (P < 0.05). (2) Compared with the blank group, there were elevated levels of interleukin-6, interleukin-18, tumor necrosis factor-α, and matrix metalloproteinase-1 in the model group (P < 0.05). Compared with the model group, the levels of interleukin-6, interleukin-18, tumor necrosis factor-α, and matrix metalloproteinase-1 were reduced in both the massage and medication groups (P < 0.05). (3) Hematoxylin-eosin staining revealed that the articular cartilage surface in the blank group was smooth, with normal chondrocyte morphology and regular arrangement. However, the articular cartilage surface in the model group appeared irregular, showing chondrocyte necrosis and dissolution in local areas, unclear tidal line structure, and no significant inflammatory cell infiltration. The massage group exhibited relatively smooth articular cartilage surface, increased chondrocyte counts, visible cell clusters, unclear tide line structure, and no significant inflammatory cell infiltration. The medication group also showed relatively smooth articular cartilage surface, increased chondrocyte counts, visible cell clusters, unclear tide line structure, and no significant inflammatory cell infiltration. The Markin score in the model group was higher than that in the other three groups (P < 0.05). To conclude, acupoint-pressing and knee-regulating therapy can effectively improve the articular cartilage ultrastructure and reduce inflammatory reactions in rats with knee osteoarthritis.

Key words: bone tissue engineering, massage, acupoint-pressing and knee-regulating therapy, knee osteoarthritis, cartilage, inflammatory factors, tissue construction