Torilin ameliorates type II collagen-induced arthritis in mouse model of rheumatoid arthritis

•Reduced CIA-induced clinical score, cellular infiltration & cartilage erosion.•Modulated CIA-activated T/B-cell & dendritic cell subpopulations in target organs.•Arrested T-cell & neutrophil infiltrations in the joints.•Inhibited anti-CII-antibodies & proinflammatory cytokines in serum or splenocytes.•Reduced inflammatory response, arthritis severity and modified cytokine imbalances.

Advancements in rheumatoid-arthritis-(RA) therapies have shown considerable progresses in the comprehension of disease. However, the development of new potential agents with relative safety and efficacy continues and natural compounds have been considered as alternatives to identify new entities. Since previous in-vivo data and our in-vitro findings showed that torilin has a strong anti-inflammatory property, we further investigated its effect against collagen-induced-arthritis-(CIA) in mice. CIA-induced DBA/1J mice were treated with torilin or methotrexate (MTX) for 5-weeks. Arthritis severity was evaluated by arthritic score and joint histopathology. Draining lymph node (dLN), joint and peripheral-blood mononuclear-cell (PBMC) counts, and activation/localization of T-/B-lymphocytes, dendritic cells (DCs) and neutrophils were examined by FACS analysis. Serum anti-type-II-collagen-(CII) antibody levels and cultured-splenocyte and serum cytokines were also evaluated. Torilin markedly reduced CIA-induced arthritic score, histopathology and leukocyte counts. Besides, torilin suppressed CIA-activated T-cells including CD3 +, CD3 +/CD69 +, CD8 +, CD4 + and CD4 +/CD25 + in dLNs or joints. It also modified CD19 + or CD20 +/CD23 + (B-cells), MHCII +/CD11c + (DCs) and Gr-1 +/CD11b + (neutrophil) subpopulations. It further depressed total anti-CII-IgG, anti-CII-IgG1 and anti-CII-IgG2a antibody productions. Moreover, while IFN-γ and IL-10 were not affected, torilin suppressed CIA-induced serum TNF-α, IL-1β and IL-6 levels. Interestingly, torilin also blocked IFN-γ, IL-17 and IL-6 cytokines while it did not affect IL-10 but enhanced IL-4 in splenocytes. These results show that torilin attenuated arthritis severity, modified leukocyte activations in dLNs or joints, and restored serum and splenocyte cytokine imbalances. Torilin may have immunomodulatory and anti-inflammatory properties with the capacity to ameliorate the inflammatory response in CIA-mice.