In this study, we investigated the mechanism of crude extract of Psammosilene tunicoides(CEPT) in the treatment of rheumatoid arthritis(RA) based on the Nod-like receptor protein 3(NLRP3) inflammasome. The collagen-induced arthritis(CIA) mouse model was established. On day 32 after the primary immunization, according to the arthritis score, the mice were randomly divided into model group, positive control(methotrexate) group, low-and high-dose CEPT groups, and normal group, with 10 mice in each group. According to the administration dose of each group, the mice were continuously administered for 21 days. Every four days during the administration, the paw edema degree, arthritis score, and spleen index of the mice were measured; histopathological examination was performed for the ankles of the mice; the contents of IL-1β and IL-18 in the serum were determined; the protein expression levels of NLRP3, caspase-1, and apoptosis-associated speck-like protein containing a CARD(ASC), as well as the mRNA expression levels of NLRP3 and caspase-1 in the ankle joints of the mice were detected. The results showed that compared with those in the model group, the mice in the positive control group and CEPT groups had significantly decreased the contents of IL-1β and IL-18 in the serum and spleen index(P<0.01), significantly lowered arthritis score and degree of paw edema(P<0.01), alleviated arthritic infiltration of the knee, and down-regulated protein and mRNA levels of NLRP3, ASC, and caspase-1 in the ankle joint(P<0.01). These results suggest that P. tunicoides may reduce the paw edema and arthritis score and alleviate the inflammatory response in CIA mice by inhibiting the expression of NLRP3. This study provides a basis for the study of immune regulation of P. tunicoides in RA.
Keywords: NLRP3 inflammasome; Psammosilene tunicoides; collagen-induced arthritis model; inflammation; rheumatoid arthritis.