Weight loss and morphometric study of intestinal mucosa in rats after massive intestinal resection: influence of a glutamine-enriched diet

Short-bowel syndrome is responsible for significant metabolic alterations that compromise nutritional status. Glutamine is considered an essential nutrient for enterocytes, so beneficial effects from supplementation of the diet with glutamine are hypothesized. PURPOSE: In this study, the effect of a diet enriched with glutamine was evaluated in rats undergoing extensive small bowel resection, with analysis of postoperative weight loss and intestinal morphometrics of villi height, crypt depth, and thickness of the duodenal and remnant jejunal mucosa. METHODS: Three groups of male Wistar rats were established receiving the following diets: with glutamine, without glutamine, and the standard diet of laboratory ration. All animals underwent an extensive small bowel resection, including the ileocecal valve, leaving a remnant jejunum of only 25 cm from the pylorus that was anastomosed lateral-laterally to the ascendant colon. The animals were weighed at the beginning and end of the experiment (20th postoperative day). Then they were killed and the remnant intestine was removed. Fragments of duodenal and jejunal mucosa were collected from the remnant intestine and submitted to histopathologic exam. The morphometric study of the intestinal mucosa was accomplished using a digital system (KS 300) connected to an optic microscope. Morphometrics included villi height, crypt depth, and the total thickness of intestinal mucosa. RESULTS: The weight loss comparison among the 3 groups showed no significant loss difference. The morphometric studies showed significantly taller duodenal villi in the glutamine group in comparison to the without glutamine group, but not different from the standard diet group. The measurements obtained comparing the 3 groups for villi height, crypt depth, and thickness of the remnant jejunum mucosa were greater in the glutamine-enriched diet group than for the without-glutamine diet group, though not significantly different from with standard-diet group. CONCLUSIONS: In rats with experimentally produced short-bowel syndrome, glutamine-enrichment of an isonitrogenous test diet was associated with an improved adaptation response by the intestinal mucosa but not reduced weight loss. However, the adaptation response in the group receiving the glutamine-enriched diet was not improved over that for the group fed regular chow.A síndrome do intestino curto é responsável por alterações metabólicas que comprometem o estado nutricional do paciente. A glutamina é nutriente essencial para os enterócitos. OBJETIVOS: Estudou-se o efeito da administração de dieta com glutamina, em ratos submetidos à ressecção subtotal do intestino delgado, avaliando a perda de peso pós-operatória e a morfometria da mucosa intestinal. MÉTODOS: Foram constituídos três grupos de ratos Wistar machos recebendo as seguintes dietas: com glutamina (grupo EG), sem glutamina (grupo EsG), e a dieta padrão do laboratório (grupo ER). A ressecção intestinal foi realizada em todos os animais incluindo-se a válvula íleo-cecal, com remanescente jejunal de apenas 25cm a partir do piloro, anastomosado látero-lateralmente ao cólon ascendente. A diferença entre o peso inicial real e ao final do experimento no 20&ordm; dia pós-operatório foi registrada antes do sacrifício. Fragmentos de mucosa do duodeno e jejuno foram colhidos e corados com hematoxilina-eosina. Realizou-se o estudo morfométrico da mucosa intestinal, por meio de sistema digital associado ao microscópio ótico. Mediu-se a altura das vilosidades, a profundidade das criptas e a extensão total da mucosa intestinal. RESULTADOS: A perda de peso entre os três grupos não diferiu estatisticamente. A análise da morfometria da mucosa intestinal mostrou diferença significativa: 1) animais do grupo Enterectomia com Glutamina (EG) apresentaram vilosidade duodenal significativamente maior que o grupo EsG (p< 0,05), mas não diferiram do grupo que recebeu dieta padrão do laboratório (ER); 2) nas medidas da vilosidade jejunal, cripta jejunal e mucosa jejunal, o grupo Enterectomia com Glutamina (EG) apresentaram maior altura, profundidade e extensão, respectivamente, em relação ao grupo Enterectomia sem glutamina (EsG) (