Effect of L-carnitine on the synthesis of nitric oxide in RAW 264·7 murine macrophage cell line.
L-Carnitine (β-hydroxy-γ-trimethyl aminobutyric acid) plays a critical role in inflammatory diseases by modulating inflammatory cell functions. Inducible nitric oxide synthase (iNOS), a proinflammatory enzyme responsible for the generation of nitric oxide (NO), has been implicated in the pathogenesis of inflammatory diseases. Mechanism of action of L-carnitine on inflammation via iNOS and nuclear factor κB (NF-κB) is unclear. In this study, we aimed to investigate the effect of L-carnitine on nitric oxide synthesis in lipopolysaccharide (LPS)-stimulated RAW 264·7 macrophage cells. For this purpose, cells were pretreated with various concentrations of L-carnitine and subsequently incubated with LPS (1 µg·ml(-1) ). NO levels, iNOS protein expression, and NF-κB activity were determined using colorimetric detection, Western blotting and transfection assays. Our results showed that treatment with L-carnitine suppressed nitric oxide production, iNOS protein expression and NF-κB activity. We demonstrated that inhibitory effect of L-carnitine on iNOS protein expression is at transcriptional level. This study may contribute to understanding the anti-inflammatory effect of L-carnitine.
Department of Biochemistry, Ankara University, Turkey.
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A
Koc
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Ozkan
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AZ
Karabay
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Sunguroglu
F
F
Aktan
D000818:Animals; D002331:Carnitine / Q000494:pharmacology*; D002460:Cell Line; D015870:Gene Expression / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D051379:Mice; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism
D016328:NF-kappa B; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D002331:Carnitine