Echinocystic acid activates PPARγ to alleviate mannan-inducedpsoriasis and psoriatic arthritis in mice

Previous studies have shown that echinocystic acid (EA) can reduce arthritis and skin damage, but the role of EA in psoriatic arthritis is unclear. This study aims to prove the role of EA in psoriatic arthritis, which was induced by intraperitoneal injection of mannan in C57BL/6J mice. The mice were divided into a control group, mannan group, mannan + EA (low-dose) group, and mannan + EA (high dose) group. Joint tissue damage was scored, and pathological changes in joint tissue and ear skin damage were examined by HE staining. Pathway enrichment of EA drug targets was performed through the target enrichment website, and the mRNA and protein expression levels of pathway-related proteins in joint tissues and ears were verified using the PCR and western blot. The results show that injection of mannan into mice resulted in joint inflammatory infiltration and tissue damage, hyperkeratosis, and acanthosis of the ear skin, while these symptoms were alleviated after high-dose EA treatment. Pathway enrichment analysis showed that the EA drug treatment target is concentrated on the PPAR pathway. The mRNA and protein results showed that the mRNA and protein expression levels of peroxisome proliferator-activated receptor γ (PPARγ) in the joint tissues and ears of mice with psoriatic arthritis decreased, and the expression of PPARγ was activated after high-dose EA treatment. In conclusion, EA increases PPARγ expression and reduces joint and skin damage in mice with psoriatic arthritis.