Objective

2

To explore the possible mechanism of

Tongfeng Decoction

（痛风汤） for preventing and treating acute gouty arthritis.

Methods

2

Sixty Wistar male rats were divided into normal group， model group， colchicine group and low-， medium- and high-dose

Tongfeng Decoction

groups according to the random number table， 10 rats in each group.

Tongfeng Decoction

of 11.34， 22.68 and 45.36 g/kg were given by gavage to low-， medium- and high-dose

Tongfeng Decoction

groups， colchicine 3.15×10

-

4

g/（kg·d） to the colchicine group， and normal saline 10 ml/（kg·d） to the normal group an

d model group respectively for 7 consecutive days. After 1 hour of gavage on day 5， rats in all groups except the normal group were modelled as acute gouty arthritis in the ankle joint of the right hind limb with the modified Coderre's method； rats in the normal group were injected with 0.2 ml of normal saline at the same location. The swelling degree of the ankle joint was measured before modelling and after 6 h， 12 h， 24 h and 48 h of modelling， respectively. HE staining was used to observe the histopathological and morphological changes in the synovial tissue of the ankle joint； immunoblotting and RT-qPCR were used to detect NOD-like receptor protein 3 （NLRP3）， apoptosis-associated speck-like protein （ASC）， cysteine aspartate protease 1 （Caspase-1）， and interleukin 1β （IL-1β） protein and mRNA expression levels in ankle synovial tissues， respectively； immunohistochemistry was used to detect the positive expression of Caspase-1 and IL-1β in ankle synovial tissues； ELISA was used to detect the tumour necrosis factor alpha （TNF-α）， IL-1β， and interleukin in serum； immunofluorescence staining was used to observe the formation of neutrophil extracellular traps （NETs） in the synovial tissues of the ankle joints.

Results

2

Compared with the normal group， rats in the model group showed elevated joint swelling at all time points， significantly increased inflammatory cell infiltration and the number of synovial cell layers in the synovial tissues of the ankle joints， elevated NLRP3， Caspase-1， ASC and IL-1β protein and mRNA expression， elevated positive expression of Caspase-1 and IL-1β， increased formation of NETs， and elevation of TNF-α， IL-6， and IL-1β in serum （

P

＜0.05）. Compared with the model group， there was an improvement in synovial cell proliferation and inflammatory cell infiltration of the ankle joint in the colchicine group， high- and medium-dose

Tongfeng Decoction

groups. In the colchicine group and the high-， medium- and low-dose

Tongfeng Decoction

groups， the degree of joint swelling， positive expression of Caspase-1， IL-1β and formation of NETs in the synovial tissue of the ankle joint， and TNF-α， IL-6 and IL-1β in serum reduced 24 h and 48 h after modelling； in colchicine group and high-dose

Tongfeng Decoction

group， NLRP3， ASC， Caspase-1， IL-1β protein and mRNA expression in the synovial tissues of ankle joints all reduced （

P

＜0.05）. The colchicine group and high-dose

Tongfeng Decoction

group were superior to the low-dose

Tongfeng Decoction

group in reducing ASC， Caspase-1， IL-1β protein and mRNA expression in the ankle synovial tissues， the positive expression of Caspase-1， as well as TNF-α， IL-6， and IL-1β level in serum （

P

＜0.05）.

Conclusion

2

Tongfeng Decoction

showed effectiveness for the prevention and treatment of acute gouty arthritis， and its mechanism may be related to the inhibition of the assembly and activation of NLRP3 inflammatory vesicles in ankle synovial tissues， the inhibition of the release of inflammatory factors， and the formation of NETs.