[Effect of heat-reinforcing needling on expression of P2X7R, NLRP3 and Caspase-1 in synovial tissues of knee joint in rabbits with cold syndrome rheumatoid arthritis].

ABSTRACT

OBJECTIVE: To observe the effects of heat-reinforcing needling on the expression of purinergic ligand-gated ion channel 7 receptor(P2X7R)，Nodlike receptor protein 3(NLRP3) and Caspase-1 in synovium tissues of knee joint of rabbits with cold syndrome rheumatoid arthritis(RA)，so as to explore the anti-inflammatory mechanism of heat reinforcing needling in the treatment of RA. METHODS: Thirty male New Zealand white rabbits were randomly divided into normal group, model group, reinforcing-reducing needling group(RRG), heat-reinforcing needling group(HRG), and antagonist group(AG), with 6 rabbits in each group.The model of cold syndrome RA was established by ovalbumin combined with Freund's adjuvant and cryogenic freezing. Rabbits of RRG and HRG were treated with corresponding acupuncture techniques on both sides of "Zusanli"(ST36) for 30 min, once a day for 7 days; Rabbits of the AG was intraperitoneally injected with A438079(2.5 mg/kg), once a day for 7 days. After intervention, color Doppler ultrasound was used to observe the joint cavity effusion, synovial thickness and internal blood flow signal.The histomorphological changes of synovial tissues were observed by HE staining. Quantitative real-time PCR method was used to detect the mRNA expression levels of P2X7R, NLRP3, and Caspase-1 in synovial tissues. Western blot was used to detect the protein expression of interleukin(IL)-1ß, IL-6 and tumor necrosis factor(TNF)-α in synovial tissues. RESULTS: Compared with the normal group, the synovial tissues in the model group was thickened, linear and punctate blood flow signals were increased, joint effusion was obvious, synovial coating cells were enlarged, the synovial matrix was severely hyperplasia, inflammatory cells infiltration was obvious.The mRNAs expression levels of P2X7R, NLRP3, Caspase-1 and IL-1ß, IL-6, TNF-α proteins in synovial tissues were significantly increased(P<0.01). Compared with model group, abnormal blood flow signals, synovial thickness, joint effusion, proliferation of synovial matrix, inflammatory cell infiltration and synovial coating cells in the RRG, HRG and AG were improved. The mRNAs expression levels of P2X7R, NLRP3, Caspase-1 and IL-1ß, IL-6, TNF-α proteins in synovial tissues were decreased in the RRG, HRG and AG (P<0.05, P<0.01). Compared with the RRG, the above indexes were lower in the HRG and AG (P<0.05, P<0.01).There was no significant difference in all indexes above between the HRG and AG (P<0.01, P<0.05). CONCLUSION: Heat reinforcing needling can improve synovial inflammation of RA, which may be related to regulating the expressions of P2X7R/NLRP3/Caspase-1 signaling pathway.