Objective To observe the effects of heat-reinforcing needling on the expression of purinergic ligand-gated ion channel 7 receptor(P2 X7 R)

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 P2 X7 R

NLRP3

and Caspase-1 in synovial tissues. Western blot was used to detect the protein expression of interleukin(IL)-1β

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 P2 X7 R

NLRP3

Caspase-1 and IL-1β

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 P2 X7 R

NLRP3

Caspase-1 and IL-1β

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 P2 X7 R/NLRP3/Caspase-1 signaling pathway.