Objective To observe the effect of heat-reinforcing needling on the expression of serum inflammatory factors and autophagy of knee synovial tissue in rheumatoid arthritis(RA) rabbits with cold syndrome

so as to explore its mechanism of anti-inflammatory in the treatment of RA. Methods Fifty rabbits were randomly divided into normal

model

heat-reinforcing needling

inhibitor and agonist groups(n=10 rabbits in each group). The model of RA with cold syndrome was established by Freund's adjuvant and ovalbumin mixed solution injection combined with freezing and wind-cold dampness method. Heat-reinforcing needling was applied at “Zusanli”(ST36) for 30 min

once a day for 14 days. Rabbits of the inhibitor and agonist groups were given intraperitoneally injected with autophagy inhibitor 3-methyladenine(3-MA) or autophagy agonist rapamycin

once every 2 days for 7 days. The knee circumference and skin temperature of the rabbits in each group were measured. Color doppler ultrasonography was applied to examine the synovial membrane

joint effusion and blood flow signals in the knee joints of the rabbits in each group. Serum tumor necrosis factor(TNF)-α

interleukin(IL)-1β

IL-6 and C-creactive protein(CRP) were detected by ELISA. Transmission electron microscopy was applied to observe the ultrastructure and autophagosomes of synovial cells. The protein expressions of autophagy-related protein Atg5

serine/threonine protein kinase-dysregulated 51-like kinase 1(ULK1)

microtubule-associated protein light chain 3 B(LC3 B)

and Beclin-1 were detected by Western blot. Fluorescence quantitative PCR was used to detect the mRNA expressions of NOD-like receptor 3(NLRP3) and nuclear factor-κB(NF-κB). Results Compared with the normal group

the circumference of the knee joint was increased(P<0.01)

the skin temperature was decreased(P<0.01)

the knee joint synovium was thickened and the blood flow signal was abundant

the contents of serum TNF-α

IL-1β

IL-6

and CRP were increased(P<0.01)

the protein expressions of Atg5

ULK1

Beclin-1 and LC3 BⅡ/LC3 BⅠof synovial tissue were significantly decreased(P<0.01)

the mRNA expressions of NLRP3 and NF-κB were increased(P<0.01) in the model group. In comparison with the model and inhibitor groups

the circumference of the knee joint was decreased(P<0.01)

whlie the skin temperature was increased(P<0.01)

the synovial membrane became thinner and the blood flow signal was wea-kened

the contents of TNF-α

IL-1β

IL-6 and CRP were decreased(P<0.01)

the protein expressions of Atg5

ULK1

Beclin-1 and LC3 B Ⅱ/LC3 B Ⅰ were increased(P<0.01)

and the mRNA expressions of NLRP3 and NF-κB were decreased(P<0.01) in the heat-reinforcing needling and agonist groups. Conclusion Heat-reinforcing needling can alleviate the inflammatory response of the knee joint synovium in RA rabbits with cold syndrome

which may be related to its function in enhancing the autophagy activity of synovial cells and inhibiting the synthesis and release of inflammatory factors TNF-α

IL-1β

IL-6 and CRP.