Simultaneous comparison of L-NAME and melatonin effects on RAW 264.7 cell line’s iNOS production and activity

Abstract

Background: NO (nitric oxide) inhibition could be used forevaluating the drug’s efficacy for NO-mediated inflammatory disorders. The aim of this study was to investigate theinfluence of L-NAME and melatonin on different NO production levels in RAW 264.7 cell line as an in vitro modelfor inflammatory diseases.Materials and methods: RAW 264.7 macrophage cell linewas used to compare the effects of L-NAME and melatoninon basal and Lipopolysaccharide (LPS)-induced iNOSlevels. The cells were treated using L-NAME and melatonin for 1 h, afterward incubated with/without LPS for 8and 24 h. Finally, iNOS mRNA, protein, activity, and nitriteconcentrations were evaluated.Results: Inhibition rate of nitrite by 1 mM L-NAME compared with LPS control were 78% and 80% during 8 and24 h, respectively. Real-time PCR showed that in the LPStreated group, 1 mM L-NAME could result in 14% increaseof iNOS-mRNA compared with the control group during8 h. Dose-dependent activity of iNOS in LPS-induced cellsfrom non-treated to 4 mM L-NAME showed 79% reduction while at the same concentrations of melatonin thisdecrease was 32% (p-value