| Objective: To explore the effects of knee three needles on bone metabolism and microstructure in knee osteoarthritis (KOA) rats by regulating the peroxisome proliferator-activated receptor gamma (PPARγ)/nuclear factor kappa B (NF-κB) pathway. Methods: Sodium iodoacetate solution was injected into the joint cavity to construct KOA rats. The successfully modeled rats were assigned into KOA group, knee three needles group (knee three needles treatment), and knee three needles+GW9662 group (knee three needles treatment+tail vein injection of 1 mg/kg GW9662), with 12 rats per group. There were 12 animals in the normal control (NC) group. The NC group and KOA group received intravenous injection of an equal amount of physiological saline once a day for 5 consecutive days per week, for a total of 3 weeks of treatment. The pain behavior of each group was tested ［paw withdrawal threshold (PWT), paw withdrawal latency (PWL)］. The enzyme-linked immunosorbent assay (ELISA) was used to detect the expression levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6, and bone metabolism indicators ［type I collagen C-terminal peptide (CTX-Ⅰ), osteoprotegerin (OPG), tartrate-resistant acid phosphatase (TRACP), and receptor activator of nuclear factor κB ligand (RANKL)］. Micro-CT was used to analyze the changes in the bone microstructure of the rat knee joint ［including trabecular thickness (Tb.Th), trabecular number (Tb.N), structure model index (SMI), trabecular separation (Tb.Sp), bone mineral density (BMD), and bone volume/tissue volume ratio (BV/TV)］. Hematoxylin and eosin (HE) staining and toluidine blue staining were implemented to measure pathological changes in knee cartilage tissue. In addition, Western blot was used to measure the expression of PPARγ/NF-κB pathway proteins in knee cartilage tissue. Results: The cells in each layer of cartilage tissue in the NC group were arranged neatly and distributed evenly. The surface of the cartilage tissue in the KOA group was uneven, with reduced cells, disordered arrangement, and a large number of vacuoles visible. The surface of the cartilage tissue in the knee three needles group was relatively flat, with an increase in the number of cells and a decrease in vacuoles. The surface of the cartilage tissue in the knee three needles+GW9662 group was uneven, with a further decrease in cell number and an increase in vacuoles. Compared with the NC group, the KOA group showed decreases in PWL, PWT, OPG, Tb.Th, Tb.N, BMD, BV/TV, and PPARγ, along with increases in Mankin score, CTX-Ⅰ, TRACP, RANKL, TNF-α, IL-1β, IL-6, SMI, Tb.Sp, and the ratio of p-NF-κB P65 to NF-κB P65 (P<0.05). Compared with the KOA group, the knee three needles group exhibited increases in PWL, PWT, OPG, Tb.Th, Tb.N, BMD, BV/TV, and PPARγ, and decreases in Mankin score, CTX-Ⅰ, TRACP, RANKL, TNF-α, IL-1β, IL-6, SMI, Tb.Sp, and the p-NF-κB P65/NF-κB P65 ratio (P<0.05). The knee three needles+GW9662 group reversed the changes in the above factors induced by the knee three-needle acupuncture intervention (P<0.05). Conclusion: Knee acupuncture improves bone metabolism and microstructure in KOA rats by activating the PPARγ/NF-κB pathway. |
