Treatment with Rutin - A Therapeutic Strategy for Neutrophil-Mediated Inflammatory and Autoimmune Diseases: - Anti-inflammatory Effects of Rutin on Neutrophils.

OBJECTIVES

Neutrophils represent the front line of human defense against infections. Immediately after stimulation, neutrophilic enzymes are activated and produce toxic mediators such as pro-inflammatory cytokines, nitric oxide (NO) and myeloperoxidase (MPO). These mediators can be toxic not only to infectious agents but also to host tissues. Because flavonoids exhibit antioxidant and anti-inflammatory effects, they are subjects of interest for pharmacological modulation of inflammation. In the present study, the effects of rutin on stimulus-induced NO and tumor necrosis factor (TNF)- productions and MPO activity in human neutrophils were investigated.

METHODS

Human peripheral blood neutrophils were isolated using Ficoll-Hypaque density gradient centrifugation coupled with dextran T500 sedimentation. The cell preparations containing > 98% granulocytes were determined by morphological examination through Giemsa staining. Neutrophils were cultured in complete Roswell Park Memorial Institute (RPMI) medium, pre-incubated with or without rutin (25 μM) for 45 minutes, and stimulated with phorbol 12-myristate 13-acetate (PMA). Then, the TNF, NO and MPO productions were analyzed using enzyme-linked immunosorbent assay (ELISA), Griess Reagent, and MPO assay kits, respectively. Also, the viability of human neutrophils was assessed using tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), and neutrophils were treated with various concentrations of rutin (1 - 100 μM), after which MTT was appended and incubated at 37ºC for 4 hour.

RESULTS

Rutin at concentrations up to 100 μM did not affect neutrophil viability during the 4-hour incubation period. Rutin significantly decreased the NO and TNF- productions in human peripheral blood neutrophils compared to PMA-control cells ( < 0.001). Also, MPO activity was significantly reduced by rutin ( < 0.001).

CONCLUSION

In this study, rutin had an anti-inflammatory effect due to its inhibiting NO and TNF productions, as well as MPO activity, in activated human neutrophils. Treatment with rutin may be considered as a therapeutic strategy for neutrophil-mediated inflammatory/ autoimmune diseases.