Alterations in the intestinal wall due to protein malnutrition in rats: Evaluation of the rupture strength and the tissue's collagen

Abstract

Purpose:To study the effect of protein malnutrition on the intestinal wall of rats by evaluating alterations in the rupture force and dosing tissue collagen in the ileum and distal colon. Methods: One hundred and twenty rats, that had an average weight of 100g, were used. They received water and a standard diet with 20% protein during 7 days for adaptation to the diet itself and to environmental conditions. After that period, the animals were randomly distributed in two groups of 60 rats each: Group 1 -the animals received a control diet with 20% casein for 21 days; Group 2 -hypoprotein diet with 2% casein for 21 days. After the adaptation period, 12 animals of each group were sacrificed at 5 moments: the beginning of experimental period (M0), 4° day (M1), 7° day (M2), 14° day (M3) and 21° day (M4). The diet to the other rats was maintained until the last sacrifice. The following variables were evaluated: body weight, blood albumin rate, tissue's hydroxyproline, hydroxyproline/total protein ratio and rupture strength in the intestinal wall of the ileum and the distal colon. Results: It was observed that the rupture strength in the ileum segment and distal colon was lower in malnourished animals (Group 2); the loss of mechanical resistance was higher in the distal colon segment than in the ileum probably due to the smaller concentration of tissue collagen in the distal colon. Conclusion: Protein malnutrition induces the loss of mechanical resistance of the ileum and distal colon and may be associated with a smaller percentage of collagenous tissue formation in the intestinal wall. Key words: Protein Malnutrition. Anastomosis, Surgical. Tensile Strength. Collagen. Rats. RESUMO Objetivo:Avaliar o efeito da desnutrição protéica na parede intestinal do rato através da medida de força de ruptura e dosagem do colágeno tecidual no íleo e cólon distal. Métodos: Foram utilizados 120 ratos, pesando em média 100g, que receberam durante 07 dias uma dieta padrão, contendo 20% de caseína para adaptação dos animais as condições do biotério. Após esse período os animais foram divididos em dois grupos de 60, o controle denominado grupo um que recebeu a dieta padrão, e o grupo teste denominado grupo dois, que recebeu dieta hipoprotéica contendo 2% de caseína. Os dois grupos receberam suas respectivas dietas por um período de 21 dias. Após esse período iniciou-se o sacrifício seqüencial dos animais em ambos os grupos, em número de 12 animais em cada momento, correspondendo ao dia Zero (MO), 4º dia (M1), 7º dia (M2), 14º dia (M3), e 21º dia (M4) sendo mantida a mesma dieta até o final do sacrifício. Em cada momento foram avaliados o peso corpóreo, albumina sanguínea, hidroxiprolina tecidual, relação hidroxiprolina/ proteína tecidual e a força de ruptura no segmento ileal e cólico dos animais. Resultados: Observou-se que a força de ruptura do segmento ileal e do cólon distal foi menor nos animais desnutridos (Grupo 2). A perda da resistência mecânica foi maior no segmento do cólon distal do que no segmento ileal, provavelmen...

Aging Skin: Nourishing from the Inside Out, Effects of Good Versus Poor Nitrogen Intake on Skin Health and Healing

“…This observation is concomitant with compromised collagen synthesis in other organs such as the intestinal wall [21]. These findings indicate that skin collagen integrity is strictly entangled with protein malnutrition.…”

Healing of displaced condylar process fracture in rats submitted to protein undernutrition

“…Protein undernutrition is successfully induced by a specially prepared hypoprotein diet (Santos et al, 2004). Low body weight has been demonstrated in experimental protein undernutrition (Nakajima et al, 2008). Undernourished fractured rats presented significant weight loss, with low recovery, indicating high catabolism in this group.…”

In Situ Study of the Effect of Naringin, Talinolol and Protein-Energy Undernutrition on Intestinal Absorption of Saquinavir in Rats

“…Various studies have demonstrated that undernourishment has dramatic effects on small intestinal mucosal structure and transport activity [7,50]. The consequent effect of malnutrition on nutrients and drugs absorption is highly variable and contradictory [51], being responsible for either increase or decrease in absorption, whether measured in terms of rate, as absorption rate constant, and in terms of extent, as area under the curve (AUC) [5].…”

“…The higher k a obtained in PEU animals compared with WN animals may be a consequence of changes in the absorptive membrane, like altered mucosal protein concentrations (absorptive and secretory carriers, and also metabolic enzymes), reduced villus heights and crypt depths, and also disrupted intestinal membrane integrity or damage in tight junctions [7,50,52–55]. In this nutritional status, the number of protein carriers would be decreased, and the repercussion of inhibitors of influx or efflux transport would have a minor effect.…”