The aim of the present study was to investigate the efficacy of
fucoxanthin on
endotoxin-induced
uveitis (EIU) in rats. The effects of
fucoxanthin on
endotoxin-induced leucocyte and
protein infiltration,
nitric oxide (NO),
prostaglandin (PG)-E2 and tumour
necrosis factor (
TNF)-alpha concentrations in rat aqueous humour, as well as on the
cyclooxygenase (COX)-2 and
inducible nitric oxide synthase (iNOS)
protein expression in a mouse macrophage cell line (RAW 264.7 cells) were studied. EIU was induced in male Lewis rats by a footpad injection of
lipopolysaccharide (LPS). Immediately after the LPS injection, either 0.1, 1 or 10mgkg(-1) of
fucoxanthin was injected intravenously. The aqueous humour was collected 24hr later from both eyes, and both the number of cells infiltrating into the aqueous humour and the aqueous humour
protein concentration were measured. The levels of
PGE2, NO and
TNF-alpha were determined by
enzyme-linked
immunosorbent assay. The RAW 264.7 cells were pretreated with various concentrations of
fucoxanthin for 24hr and subsequently incubated with LPS for 24hr. COX-2 and iNOS
protein expression was analysed by the Western blotting method. Levels of
PGE2, NO and
TNF-alpha production were determined.
Fucoxanthin suppressed the development of EIU in a dose-dependent fashion. Treatment with
fucoxanthin resulted in a reduction in
PGE2, NO and
TNF-alpha concentrations in the aqueous humour. The expression of COX and iNOS
protein in the
fucoxanthin treated RAW264.7 cells decreased significantly compared to that the LPS group. It also significantly reduced the concentration of
PGE2, NO and
TNF-alpha production in the medium of cells. The present result indicate
fucoxanthin suppresses the
inflammation of EIU by blocking the iNOS and COX-2
protein expression and its anti-inflammatory effect on eye is comparable with the effect of predinisolone used in similar doses.