Effectiveness of Huai Qi Huang Granules on Juvenile Collagen-induced Arthritis and Its Influence on Pyroptosis Pathway in Synovial Tissue.

Huai Qi Huang (HQH) exerts great effects in clinic, such as anti-inflammation, immune-regulation, anti-cancer, and so on. However, the mechanism by which HQH protects juvenile idiopathic arthritis (JIA) is obscure. Thus, we explored deeply the protective mechanisms in juvenile collagen-induced arthritis (CIA) rat model. Pyroptosis is Gasdermin D (GSDMD)-dependent programmed cell death, involved in many diseases, such as sepsis. We investigated whether GSDMD-induced pyroptosis take part in mechanisms of juvenile CIA arthritis. Juvenile Wistar rats (3-4 weeks) were injected intradermally with fully emulsified bovine type II collagen and complete Freund's adjuvant to establish CIA rat models. Later, the CIA rats received oral administration of HQH (4.16 g/kg) once a day from the day 21 of modeling, with the treatment lasting for 28 days. Varieties of indicators were measured for evaluation of anti-inflammation effect of HQH, including hind paw swelling, arthritis scores, micro CT, and histopathological changes and the level of pro-inflammatory cytokines in the serum, including tumor necrosis factor alpha (TNF-±) and interleukin-18 (IL-18). The expression of GSDMD and caspase-1 in the joint synovial tissues was detected. The results demonstrated that the expression of the pyroptotic protein GSDMD and its upstream caspase-1 was significantly increased in the synovial tissues of CIA rats. The treatment of HQH ameliorated the symptoms in CIA rats, reduced levels of pro-inflammatory cytokines and hind paw swelling, down-regulated the expression of GDSMD and caspase-1. GSDMD-induced pyroptosis participated in the pathogenesis of CIA rats. The study supported that HQH can effectively improve joints inflammation of juvenile collagen-induced arthritis rats by inhibiting pyroptosis pathway in the joint synovial tissues.