1. Academic Validation
  2. The spin trap 5,5-dimethyl-1-pyrroline N-oxide inhibits lipopolysaccharide-induced inflammatory response in RAW 264.7 cells

The spin trap 5,5-dimethyl-1-pyrroline N-oxide inhibits lipopolysaccharide-induced inflammatory response in RAW 264.7 cells

  • Life Sci. 2012 Mar 10;90(11-12):432-9. doi: 10.1016/j.lfs.2011.12.018.
Zili Zhai 1 Sandra E Gomez-Mejiba Hua Zhu Florea Lupu Dario C Ramirez
Affiliations

Affiliation

  • 1 Experimental Therapeutics Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA. zlzhai@yahoo.com
Abstract

Aim: Exposure of macrophages to lipopolysaccharide (LPS) induces oxidative and inflammatory stresses, which cause cell damage. Antioxidant and anti-inflammatory properties have been attributed to the nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO), commonly used in free radical analysis, but these aspects of DMPO have been little explored. In this study, we sought to establish the anti-inflammatory activity of DMPO, presumably by removing free radicals which otherwise help activate inflammatory response and damage cells.

Main methods: RAW 264.7 macrophages were treated with LPS and/or DMPO for different time points, cell damage, production of inflammatory mediators, inducible nitric oxide synthase (iNOS) expression, NF-κB p65 activation, phosphorylation of MAPKs and Akt, and intracellular Reactive Oxygen Species (ROS) were determined.

Key findings: After cells were treated with LPS and/or DMPO for 24 h, DMPO reduced the LPS-induced inflammatory response as indicated by downregulated iNOS expression and production of inflammatory mediators. Accordingly, DMPO protected cells from LPS-induced cytotoxicity. In order to understand the mechanistic basis of these DMPO effects, the NF-κB p65 activation and the phosphorylation of MAPKs and Akt were examined. We found, by assaying cells treated with LPS and/or DMPO for 15-60 min, that DMPO inhibited the phosphorylation of MAPKs, Akt, and IκBα, and reduced the NF-κB p65 translocation. Furthermore, we demonstrated that DMPO inhibited LPS-induced ROS production.

Significance: DMPO showed the anti-inflammatory activity and attenuated LPS-induced cell damage, most likely by reducing ROS production and thus preventing the subsequent inflammatory activation and damage.

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