ABSTRACT
BACKGROUND: Dietary flavonols may play an important role in the adjunct therapy of chronic inflammation. The availability of therapeutic formulations of pentahydroxyflavone glycoside, rutoside (RU), led us to investigate the ability of this molecule to modulate the release of various proinflammatory mediators from human activated macrophages in vitro and to ameliorate arthritic markers in a rat model. METHODS: RU was added simultaneously to human macrophages during their activation. Cells were then analyzed for inflammation-related gene expression using a specific array, and cell supernatants were collected to measure inflammatory mediators. RU was also injected into adjuvant-induced arthritic rats, and disease progression and body weight were evaluated until 50 days after injection. Sera and peritoneal macrophages were also collected to quantify the RU effect on various inflammatory markers. RESULTS: RU inhibited inflammation-related gene expression in activated human macrophages and the release of nitric oxide, tumor necrosis factor-alpha, interleukin (IL)-1, and IL-6 from these cells. In a rat model, RU inhibited clinical signs of chronic arthritis, correlating with decreased levels of inflammatory cytokines detected in rat sera and macrophage supernatants. CONCLUSION: Thus, RU may have clinical value in reducing inflammatory manifestations in human arthritis and other inflammatory diseases.
Subject(s)
Arthritis, Experimental/metabolism , Arthritis, Experimental/physiopathology , Inflammation Mediators/antagonists & inhibitors , Macrophages/metabolism , Rutin/pharmacology , Animals , Arthritis, Experimental/genetics , Arthritis, Experimental/pathology , Body Weight/drug effects , Cells, Cultured , Chronic Disease , Cytokines/antagonists & inhibitors , Cytokines/genetics , Dose-Response Relationship, Drug , Female , Humans , Interleukin-1/antagonists & inhibitors , Interleukin-6/antagonists & inhibitors , Macrophages/drug effects , Macrophages, Peritoneal/drug effects , Macrophages, Peritoneal/metabolism , Nitric Oxide/antagonists & inhibitors , Rats , Rats, Inbred Lew , Rutin/administration & dosage , Transcription, Genetic/drug effects , Tumor Necrosis Factor-alpha/antagonists & inhibitorsABSTRACT
Pentahydroxyflavone dihydrate, quercetin (QU) is one of common flavonols biosynthesized by plants and has been suggested to modulate inflammatory responses in various models. In the present study, we investigated in vivo effects of oral or intra-cutaneous QU in chronic rat adjuvant-induced arthritis (AA). Growth delay and arthritic scores were evaluated daily after AA induction in Lewis rats. Oral administration of QU (5 x 160 mg/kg) to arthritic rats resulted in a clear decrease of clinical signs compared to untreated controls. Intra-cutaneous injections of lower doses (5 x 60 mg/kg) of QU gave similar anti-arthritic effects, while 5 x 30 mg/kg concentrations were inefficient in this respect. Finally, injection of relatively low QU doses (5 x 30 mg/kg) prior to AA induction significantly reduced arthritis signs. As QU was suggested to inhibit macrophage-derived cytokines and nitric oxide (NO), we then analyzed macrophage response ex vivo. Anti-arthritic effects of QU correlated with significant decrease of inflammatory mediators produced by peritoneal macrophages, ex vivo and in vitro. These data indicate that QU is a potential anti-inflammatory therapeutic and preventive agent targeting the inflammatory response of macrophages.
