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.
Recent evidence suggests that lipopolysaccharide (LPS) endotoxaemia in a rat causes significant mucosal injury. Our objective was to determine the effects of glutamine (Gln) on Toll-like receptor 4 (TLR-4), myeloid differentiation factor 88 (Myd88) and tumour necrosis factor (TNF)-alpha receptor-associated factor 6 (TRAF6) expression in intestinal mucosa following LPS endotoxaemia in a rat. For this purpose, male Sprague-Dawley rats were assigned randomly to one of three experimental groups of 10 rats each: (i) control rats underwent intraperitoneal (i.p.) injection of sterile saline once a day; (ii) rats were treated with LPS given i.p. once a day at a dose of 10 mg/kg for 48 h (two doses); and (iii) rats were pretreated with oral Gln given in drinking water (2%) 48 h before and following injection of LPS. Intestinal mucosal parameters, enterocyte proliferation and apoptosis were determined at death. TLR-4 and MyD88 mRNA expression was measured with reverse transcription-polymerase chain reaction (RT-PCR). TLR-4 and MyD88 protein expression were analysed by Western immunoblotting. We observed a statistically significant (P < 0.05) decrease in mucosal weight, mucosal DNA and enterocyte proliferation and a significant increase in enterocyte apoptosis in rat intestine, following LPS administration. These changes were attenuated significantly by dietary Gln. Expression of TLR-4, MyD88 and TRAF6 mRNA in the mucosal ileum was significantly higher in LPS rats versus control rats (P = 0.0006, P = 0.0015, P = 0.03, respectively) as well as TLR-4 and MyD88 protein expression. The administration of Gln reduced significantly the expression of TLR-4, MyD88 and TRAF6 (P = 0.023, P = 0.014, P = 0.035, respectively) mRNA as well as TLR-4 and MyD88 protein expression in ileum compared to LPS animals. We did not find a significant change in the expression of TLR-4, MyD88 or TRAF6 in the jejunum of different groups. We conclude that treatment with Gln was associated with down-regulation of TLR-4, MyD88 and TRAF6 expression and concomitant decrease in intestinal mucosal injury caused by LPS endotoxaemia in a rat.
Kessel
A
A
Allergy and Clinical Immunology, Bnai Zion Medical Center, The Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel. aharon.kessel@b-zion.org.il
Toubi
E
E
Pavlotzky
E
E
Mogilner
J
J
Coran
A G
AG
Lurie
M
M
Karry
R
R
Sukhotnik
I
I
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology; D049109:Cell Proliferation / Q000187:drug effects; D015536:Down-Regulation / Q000187:drug effects*; D019446:Endotoxemia / Q000188:drug therapy / Q000276:immunology* / Q000473:pathology; D005973:Glutamine / Q000494:pharmacology* / Q000627:therapeutic use; D007413:Intestinal Mucosa / Q000276:immunology / Q000473:pathology; D007421:Intestine, Small / Q000276:immunology / Q000473:pathology; D008070:Lipopolysaccharides / Q000633:toxicity; D008297:Male; D053594:Myeloid Differentiation Factor 88 / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D048029:TNF Receptor-Associated Factor 6 / Q000096:biosynthesis / Q000235:genetics; D051197:Toll-Like Receptor 4 / Q000096:biosynthesis* / Q000235:genetics
D008070:Lipopolysaccharides; D053594:Myeloid Differentiation Factor 88; D012333:RNA, Messenger; D048029:TNF Receptor-Associated Factor 6; C495347:Tlr4 protein, rat; D051197:Toll-Like Receptor 4; D005973:Glutamine