Alanyl-glutamine restores maternal deprivation-induced TLR4 levels in a rat neonatal model

Background & aims: Increased intestinal permeability of Irritable bowel syndrome (IBS) patients has been recently associated with a decreased level of glutamine synthetase. Neonatal maternal deprivation (NMD) is considered as an IBS-like model. The aim of our study was to investigate whether early nutritional intervention with glutamine may attenuate the deleterious impact of early life stress on gut barrier function in NMD. Methods: 124 rat pups were separated from their dam 3 h daily during postnatal days 2-14, or left undisturbed (NS). Separated rats received by gavage either with alanyl-glutamine (GLN), an isonitrogenous amino acid mix (AA, control) or an equal amount of drinking water (H(2)O). Production of cytokines was measured by multiplex, expression of COX-2, PPAR gamma, tight junction proteins and TLR4 by western blot. Intestinal permeability was studied by Lactulose/Mannitol test. Results: Treatment of pups with GLN or AA abolished the decrease in body weight observed in NMD. Treatment with GLN decreased in the colon (i) TLR4 expression at D20, (ii) IL-2 and -10 productions at D60 (iii) protein expression of occludin at D20 compared to AA. GLN also decreased colon expression of COX2 and PPAR gamma at D60 compared to NS. Colon production of IFN gamma is significantly reduced by GLN compared to H(2)O. No significant change in intestinal permeability was observed. Conclusions: These results showed that an early nutritional intervention with alanyl-glutamine specifically abolished the up-regulation of TLR4 expression in NMD. Glutamine may be evaluated as a potential treatment for IBS patients. (C) 2011 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.