Glutamine supplementation and deprivation: effect on artificially reared rat small intestinal morphology.
The mechanisms of how glutamine benefits critically ill patients have not been established. The purpose of this study was to determine the effects of dietary and endogenously produced glutamine on small intestinal morphology using light and transmission electron microscopy in artificially reared rat pups. It was hypothesized that deprivation of dietary glutamine leads to intestinal disease that is exacerbated by inhibition of glutamine synthetase by methionine sulfoximine (MS). Rat pups were placed into five different test groups: The first was a reference group that was reared by their mother. The other four groups were reared artificially and received a 10% Travasol amino acid solution at 5 g/kg per day, which does not contain glutamine, added to a mixture containing carbohydrates, lipids, and vitamins. This dose was chosen because it represents an approximation of the amount of glutamine these rats would be receiving in a normal rat diet (approximately 40 g/kg per day total protein, 10 to 15% of which is glutamine + glutamate). The glutamine was manipulated by adding glutamine (Q) or MS or both. The four groups were as follows: MS-Q-, MS-Q+, MS+Q-, and MS+Q+. Light microscopy revealed the greatest blunting of villus height in the ileum of rats from the MS+Q- group when compared with the MS-Q+ group (123 +/- 48.9 micro m versus 207 +/- 36 microm, p < 0.05). The other two groups exhibited intermediate villus heights, but all were shorter than the villi from the mother-reared animals. The number of villi per unit length of bowel was also lowest in the animals that were treated with MS and not provided with dietary glutamine. Transmission electron microscopy demonstrated breakdown of the epithelial junctions in the glutamine-deprived and glutamine synthetase-inhibited intestines. Glutamine-deprived animals also displayed sloughing of microvilli, decreased actin cores, and degeneration of the terminal web. In summary, these studies support the hypothesis that glutamine is involved with maintenance of intestinal epithelial integrity.
Division of Neonatology, Department of Pediatrics, J. Hillis Miller Health Center, University of Florida College of Medicine, Gainesville, Florida 32610, USA.
Bradley
B
Potsic
Nicolette
N
Holliday
Pat
P
Lewis
Donald
D
Samuelson
Vincent
V
DeMarco
Josef
J
Neu
D000596:Amino Acids / Q000008:administration & dosage / Q000737:chemistry; D000818:Animals; D001835:Body Weight; D019587:Dietary Supplements; D004573:Electrolytes; D005260:Female; D005947:Glucose; D005974:Glutamate-Ammonia Ligase / Q000037:antagonists & inhibitors / Q000378:metabolism; D005973:Glutamine / Q000008:administration & dosage* / Q000378:metabolism*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism / Q000648:ultrastructure; D007421:Intestine, Small / Q000033:anatomy & histology* / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008717:Methionine Sulfoximine / Q000494:pharmacology; D010288:Parenteral Nutrition; D057947:Parenteral Nutrition Solutions; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012996:Solutions
D000596:Amino Acids; D004573:Electrolytes; D057947:Parenteral Nutrition Solutions; D012996:Solutions; C545824:amino-acid, glucose, and electrolyte solution; D005973:Glutamine; D008717:Methionine Sulfoximine; D005974:Glutamate-Ammonia Ligase; D005947:Glucose