Abstract：OBJECTIVE: To study the expression of Toll-like receptor 4 (TLR-4) and caspase-3 in the intestine of neonatal rats with necrotizing enterocolitis (NEC), and explore the protective effects and possible regulatory mechanisms of glutamine (Gln) in NEC. METHODS: Sixty premature rats were randomly divided into three groups (n=20 each): control, NEC model and Gln intervention group. NEC model was prepared by formula feeding, hypoxia and cold stress. The Gln intervention group was also subjected to hypoxia and cold stress but was fed with formula containing Gln (0.3 g/kg). Two days later, the rats were sacrificed and the intestine tissues were obtained. The histological changes of ileal tissues were observed by hemetoxylin and eosin staining. The expression of caspase-3 and TLR-4 protein in the jejunum, ileum and colon were detected by inmunohistochemistry. The expression of TLR-4 mRNA in the jejunum, ileum and colon were detected by RT-PCR. RESULTS: Compared with the control group, the histological score of ileal tissues, and the expression of caspase-3, TLR-4 protein and TLR-4 mRNA in the NEC model group increased significantly (P＜0.01). Gln intervention decreased significantly the histological score of ileal tissues, and the expression of caspase-3, TLR-4 protein and TLR-4 mRNA compared with the NEC model group (P＜0.05). CONCLUSIONS: TLR-4 might be involved in the pathogenesis of NEC. Gln may provide protective effects on intestine possibly through reducing the TLR-4 expression and then decreasing the apoptosis of intestinal epithelial cells.
LI Wei,ZHENG Xiao-Hui,ZHOU Wei et al. Regulatory effects of glutamine on Toll-like receptor 4 in neonatal rats with necrotizing enterocolitis[J]. CJCP, 2011, 13(5): 419-423.
［3］Auestad N, Korsak RA, Bergstrom JD, Edmond J. Milk-substitutes comparable to rat's milk, their preparation, composition and impact on development and metabolism in the artificially reared rat［J］. Br J Nutr, 1989, 61(3):495-518.
［4］Le Mandat Schultz A, Bonnard A, Barreau F, Aigrain Y, Pierre-Louis C, Berrebi D, et al. Expression of TLR-2, TLR-4, NOD2 and pNF-kappaB in a neonatal rat model of necrotizing enterocolitis［J］. PLoS One, 2007, 2(10):e1102.
［5］Medzhitov R, Janeway C Jr. The Toll receptor family and microbial recognition［J］. Trends Microbiol, 2000, 8(10): 452-456.
［6］Beutler B. Inferences, questions and possibilities in Toll-like receptor signaling［J］. Nature, 2004, 430(6996): 257-263.
［7］Medzhitov R, Preston-Hurlburt P, Janeway CA Jr. A human homologue of the Drosophila Toll protein signals activation of adaptive immunity［J］. Nature, 1997, 388(6640): 394-397.
［8］Abreu MT, Vora P, Faure E, Thomas LS, Arnold ET, Arditi M. Decreased expression of Toll-like receptor-4 and MD-2 correlates with intestinal epithelial cell protection against dysregulated proinflammatory gene expression in response to bacterial lipopolysaccharide［J］. J Immunol, 2001, 167(3): 1609-1616.
［9］Jilling T, Simon D, Lu J, Meng FJ, Li D, Schy R, et al. The roles of bacteria and TLR4 in rat and murine models of necrotizing enterocolitis［J］. J Immunol, 2006, 177(5):3273-3282.
［10］Houdijk AP, Rijnsburger ER, Jansen J, Wesdorp RI, Weiss JK, McCamish MA, et al. Randomised trial of glutamine-enriched enteral nutrition on infectious morbidity in patients with multiple trauma［J］. Lancet, 1998, 352(9130):772-776.
［11］Novak F, Heyland DK, Avenell A, Drover JW, Su X. Glutamine supplementation in serious illness: a systematic review of the evidence［J］. Crit Care Med, 2002, 30(9): 2022-2029.
［13］Kessel A, Toubi E, Pavlotzky E, Mogilner J, Coran AG, Lurie M, et al. Treatment with glutamine is associated with down-regulation of Toll-like receptor-4 and myeloid differentiation factor 88 expression and decrease in intestinal mucosal injury caused by lipopolysaccharide endotoxaemia in a rat［J］. Clin Exp Immunol, 2008, 151(2): 341-347.
