Role of Nitric Oxide and Reactive Oxygen Species in Arthritis

Abstract

A vast amount of circumstantial evidence implicates oxygen-derived free radicals, especially reactive oxygen species and nitric oxide as mediators of inflammation and/or tissue destruction in inflammatory and arthritic disorders. The aim of the current article is to overview the recent developments in this field, as it relates to the roles of nitric oxide (NO) and reactive oxygen species in the pathogenesis of this condition. The first part of the review focuses on the biochemical impact of NO and reactive oxygen species. The second part of the review deals with the novel findings related to the recently identified regulatory roles of the inducible isoform of nitric oxide synthase (iNOS) in the expression of pro-inflammatory mediators in inflammation. Reactive oxygen species can initiate a wide range of toxic oxidative reactions. These include initiation of lipid peroxidation, direct inhibition of mitochondrial respiratory chain enzymes, inactivation of glyceraldehyde-3phosphate dehydrogenase, inhibition of membrane sodium/potassium ATP-ase activity, inactivation of membrane sodium channels, and other oxidative modifications of proteins. All these toxicities are likely to play a role in the pathophysiology of inflammation. Reactive oxygen species are all potential reactants capable of initiating DNA single strand breakage, with subsequent activation of the nuclear enzyme poly (ADP ribose) synthetase (PARS), leading to eventual severe energy depletion of the cells, and necrotic-type cell death. Recently it has been demonstrated that iNOS inhibitor prevents the activation of poly (ADP ribose) synthetase, and prevents the organ injury associated with inflammation. Although the severity and duration of inflammation may dictate the timing and extent of NOS expression, it is now evident that the up-regulation of NOS can take place during sustained inflammation. Thus, induced nitric oxide, in addition to being a "final common mediator" of inflammation, is essential for the up-regulation of the inflammatory response. Furthermore, a picture of a pathway is evolving that contributes to tissue damage both directly via the formation of reactive oxygen species, with them associated toxicities, and indirectly through the amplification of the inflammatory response.

Oxidative Stress and Galactose-Deficient IgA1 as Markers of Progression in IgA Nephropathy

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Orazipone Inhibits Activation of Inflammatory Transcription Factors Nuclear Factor-κB and Signal Transducer and Activator of Transcription 1 and Decreases Inducible Nitric-Oxide Synthase Expression and Nitric Oxide Production in Response to Inflammatory Stimuli

“…However, the cellular and molecular mechanisms of the anti-inflammatory actions of orazipone remain mostly unknown. Increased NO production is associated with inflammatory diseases such as inflammatory bowel disease (Kolios et al, 2004), arthritis (Cuzzocrea, 2006), and asthma (Ricciardolo et al, 2004). NO is a small gaseous molecule synthesized in inflammatory and tissue cells by nitric-oxide synthase enzymes.…”

Antioxidant activity of 3-substituted-4-hydoxycoumarin derivatives

“…It is well known that reactive oxygen species (ROS) induce oxidative stress that is believed to be a primary factor in many diseases such as ischemia 1 , anemia 2 , asthma 3 , arthritis 4 , inflammation 5 , neurodegenerative and Parkinson's diseases 6 , Down's syndrome 7 as well as normal ageing process 8 .…”