Conclusion
Lard consumption is beneficial for active inflammatory arthritis recovery. Even SF can activate PPAR-γ and consequently attenuate inflammation.
Results
Collagen-induced arthritis (CIA) and adjuvant-induced arthritis (AIA) are induced in SD rats and C57 BL/6 mice respectively, which are fed by lard-rich diet (LRD) for 42 days with intake restriction or not. AIA SD rats are treated by representative fatty acids for 30 days. Body weight, arthritis score, and metabolic profile are periodically recorded. Monocyte distribution, cytokine/metabolites levels, gene expression, and tissue damages are investigated by flow cytometry, ELISA, colorimetry, PCR, and histological methods. After being treated by fatty acids in vitro, THP-1 monocytes and the corresponding medium are collected for ELISA, PCR, immunoblotting, and reporter gene assays. Irrespective of intake amounts, LRD decreases inflammatory cytokines and inhibits glycolysis in all rheumatic rodents. Furthermore, it alters monocyte distribution and promotes PPAR-γ expression in AIA mice. Overall evidences show that both saturated (SF) and unsaturated fatty acids (USF) from lard can attenuate inflammation by activating PPAR-γ. Silencing PPAR-γ abrogates their anti-inflammatory effects in vitro. Besides, SF can stimulate TLR4/NF-κB pathway.