Effects of different acupuncture and moxibustion methods on articular cartilage morphology and NF-κB p65/NLRP3 pathway in rats with knee osteoarthritis

Abstract

To compare the effects of filiform needling, electroacupuncture (EA) and moxibustion on articular cartilage morphology and nuclear transcription factor-κB (NF-κB) p65/ Nod-like receptor protein 3 (NLRP3) pathway in rats with knee osteoarthritis (KOA). Wistar rats were randomly divided into blank control， model, filiform needling, EA and moxibustion groups, with 8 rats in each group. The KOA model was established by injecting sodium iodoacetate into the right knee cavity. Filiform needling, EA and moxibustion groups were treated with the right side of "Dubi" (ST35) and "Neixiyan" (EX-LE5), and were given filiform needling, EA and mild moxibustion therapies for 15 min respectively, once every other day, for a total of 4 weeks. The diameter of the right knee joint was observed. The ultrastructure of knee chondrocytes was observed by transmission electron microscope. The contents of serum tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-18 were determined by ELISA. The expression levels of NF-κB p65, NLRP3, apoptosis-related speckle like protein (ASC) and TNF-α in knee cartilage were dectected by Western blot. Compared with the blank control group, the right knee joint cavity was narrowed, chondrocytes were constricted significantly, mitochondria were moderately swollen, the diameter of the right knee was increased, and the contents of serum TNF-α, IL-1β and IL-18 were increased (P<0.01), the expressions of NF-κB p65, NLRP3 and TNF-α in knee cartilage were increased (P<0.01) while the expression of ASC was decreased (P<0.01) in the model group.Compared with model group, the narrowed knee joint cavity and chondrocyte injury were improved， knee diameter decreased (P<0.01, P<0.05), and the content of serum TNF-α and the expression of NLRP3 in knee cartilage were decreased (P<0.05, P<0.01) in 3 treatment groups; the contents of serum IL-1β and IL-18, and the expression of TNF-α in knee cartilage were decreased (P<0.01, P<0.05), while the expression of ASC in knee cartilage was increased (P<0.01) in EA and moxibustion groups; the expression of NF-κB p65 in knee cartilage was decreased (P<0.01) in moxibustion group. Compared with EA group, the content of serum IL-18 was decreased (P<0.05) in moxibustion group. Filiform needling, EA and moxibustion can all reduce the formation of knee osteophytosis in KOA rats, alleviate joint cavity narrowing, improve the ultrastructure of articular cartilage, reduce the level of inflammatory factors, regulate the NF-κB p65/NLRP3 pathway. Moxibustion has the most obvious regulatory effect among the 3 treatment methods.