Effects of l-glutamine supplementation alone or with antioxidants on hydrogen peroxide-induced injury in human intestinal epithelial cells

Background and aimsIn situations of oxidative stress, l-glutamine (Gln) exhibits protective effects which may be potentiated by its combination with antioxidants. The aim of this study was to compare the effects of a Gln-antioxidants formula vs Gln alone in intestinal epithelial cell lines Caco-2 and HCT-8 submitted to hydrogen peroxide-induced oxidative injury.MethodsCells were cultured during 24 h with 0, 1, 2, 4, 8 or 16 mM Gln or isomolar Gln combined to cysteine, vitamine C, vitamine E, β-carotene, Zn and Se (Gln-AOX). After 24 h, membrane integrity was assessed by means of LDH leakage, the level of oxidative stress by analysis of 8-isoprostane concentration and cell viability by colorimetric-MTT assay.ResultsLDH activity decreased (P < 0,05) with a dose-dependent manner in both cell types with Gln-AOX whereas Gln decreased LDH release only in the Caco-2 line at 1 mM. For both cell lines, release of 8-isoprostane was not blunted by any treatment and increased paradoxically with 16 mM Gln (P < 0.05). Cell viability was higher (P < 0.05) using Gln-AOX vs Gln at 4, 8 and 16 mM in both cell lines.ConclusionsThese results suggest that Gln-AOX is more efficient than Gln alone to preserve cell membrane integrity and viability in intestinal cell lines submitted to oxidative injury.