Oleuropein aglycone, an olive oil compound, ameliorates development of arthritis caused by injection of collagen type II in the mice.

The aim of this study was to investigate the effect of oleuropein aglycone, an olive oil compound, on the modulation of the inflammatory response in mice subjected to collagen-induced arthritis (CIA). CIA was induced in mice by an intradermally injection of 100 ìl of the emulsion (containing 100 ìg of bovine type II collagen) (CII) and complete Freund's adjuvant (CFA) at the base of the tail. On day 21, a second injection of CII in CFA was administered. Mice developed erosive hind paw arthritis when immunised with CII in CFA. Macroscopic clinical evidence of CIA first appeared as peri-articular erythema and oedema in the hind paws. The incidence of CIA was 100\% by day 27 in the CII challenged mice and the severity of CIA progressed over a 35-day period with a resorption of bone. The histopathology of CIA included erosion of the cartilage at the joint. Treatment with oleuropein aglycone starting at the onset of arthritis (day 25), ameliorated the clinical signs at days 26-35 and improved histological status in the joint and paw. The degree of oxidative and nitrosative damage was significantly reduced in oleuropein aglycone-treated mice as indicated by elevated expression of inducible oxide nitric synthase (iNOS), nitrotyrosine and poly (ADP-ribose) polymerase (PARP) in the inflamed joints. Plasma levels of the pro-inflammatory cytokines were also significantly reduced by oleuropein aglycone. In this study, we demonstrate that oleuropein aglycone exerts an anti-inflammatory effect during chronic inflammation and ameliorates the tissue damage associated with CIA.