Analysis of the effects of iron and vitamin C co-supplementation on oxidative damage, antioxidant response and inflammation in THP-1 macrophages

Objectives: The aims of the study were to test the susceptibility of THP-1 macrophages to develop oxidative stress and to deploy antioxidant defense mechanisms that insure the balance between the pro- and antioxidant molecules. Design and methods: Differentiated THP-1 were incubated in the presence or absence of iron-ascorbate (Fe/As) (100/1000 mu M) and the antioxidants Trolox, BHT, alpha-Tocopherol and NAC. Results: Fe/As promoted the production of lipid peroxidation as reflected by the formation of malondialdehyde and H2O2 along with reduced PUFA levels and elevated glutathione disulfide/total glutathione ratio, a reliable index of cellular redox status. THP-1 macrophages developed an increase in cytoplasmic SOD activity due in part to high cytoplasmic SOD1. On the other hand, a decline was noted in mRNA and protein of extra-cellular SOD3, as well as the activity of GSH-peroxidase, GSH-transferase and ATOX-1 expression. Conclusions: Macrophages activated under conditions of oxidative stress do not adequately deploy a powerful endogenous antioxidant response, a situation that can lead to an enhanced inflammatory response. (C) 2011 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.