Effect of protein and vitamin B deficiency on the morpho-quantitative aspects of the myenteric plexus of the descending colon of adult rats

Abstract

We carried out this work with the purpose of studying the effects of protein and vitamin B deficiency on the morphologic and quantitative aspects of the myenteric plexus of the descending colon of adult Rattus norvegicus. Twenty-eight rats were divided in two groups, one of them receiving chow with 22% protein level (control) and the other fed with chow having 8% protein level without vitamin B supplementation, during 120 days. Whole-mounts of the descending colon were prepared and stained with Giemsa, NADH-diaphorase and NADPH-diaphorase. The undernourished rats had a body weight 11.84% less than the control group. Relative to the controls, the experimental group had a colonic area 48% smaller, 51.9% less Giemsa-stained neurons, 28.3% less NADH-diaphorase positive neurons and 24.2% less NADPH-diaphorase positive neurons.

Quantitative Study of the Myenteric Plexus of the Descending Colon of Young Rats Subjected to Intense Protein Deficiency

“…The use of animal models in investigations of food deficiency employing known and controlled diets has the advantage of increasing the knowledge about several aspects of human malnutrition (Enwonwu & Sreebny, 1970). Among these models, the rat has been used the most (Mello et al, 1995;Torrejais et al, 1995;Natali and Miranda-Neto, 1996;Sant'Ana et al, 1997;Meilus et al, 1998;Miranda-Neto et al, 1999;Natali et al, 2000;Sant'Ana et al, 2001;Castelucci et al, 2002;Araújo et al, 2003;Brandão et al, 2003;Natali et al, 2003;Mello et al, 2004). It is considered a good model for nutritional research due to its reduced size, reproductive behavior and adaptability to several diets (NRC, 1995).…”

Atrofia de neurônios do plexo mientérico do íleo de ratos submetidos à intensa carência de proteínas

“…Desta forma, os resultados de atrofia dos neurônios NADHdiaforase positivos constatados neste estudo possivelmente seja uma tentativa de manter o metabolismo dos neurônios do plexo mientérico em equilíbrio, uma vez que essa técnica possibilita visualizar neurônios com metabolismo neuronal mais ativo (MIRANDA-NETO et al, 2001), já que a NADH-diaforase é uma enzima mitocondrial (GABELLA, 1969). Azevedo et al (2007), com o mesmo modelo experimental deste estudo, avaliaram a morfometria da parede intestinal do íleo e observaram redução da espessura da parede total, da túnica muscular e da túnica mucosa. Essa atrofia associada com o aumento da população marcada pela NADHdiaforase (MOREIRA et al, 2008) pode corroborar na compreensão da atrofia neuronal evidenciada pela mesma técnica verificada neste estudo, pois a redução da parede intestinal associada ao aumento da marcação neuronal, possivelmente fez com que esses neurônios ficassem menores, no intuito de se ajustarem às necessidades fisiológicas do animal.…”

Food restriction beginning at lactation interferes with the cellular dynamics of the mucosa and colonic myenteric innervation in adult rats

“…This result can be explained by the lower supply of nutrients caused by FR, such as a reduced availability of amino acids, which can affect protein synthesis in intestinal muscles and support the occurrence of muscle atrophy. Another factor that could explain this result is an increase in protein degradation in this muscle to provide endogenous amino acids and offset the low consumption of these molecules through the diet (Araújo et al 2003). This may make endogenous amino acids available to tissues (e.g., mucosa and nerve cells) with an increased need for protein synthesis before the nutritional condition imposed.…”

“…A low-protein diet given to animals at different stages of development (e.g., gestation, lactation, and adulthood) may lead to reduced intestinal size, resulting in a higher concentration of neurons per area in segments of the small intestine (Torrejais et al 1995, Natali et al 2003 and colon (Leite-Mello et al 1997, Sant'Ana et al 1997, Castelucci et al 2002, Araújo et al 2003, Hermes et al 2008a. In the present study, we cannot attribute the intestinal reduction to the higher number of neurons observed in the FR animals compared with normally fed animals because the quantification of these cells was performed per myenteric ganglion and not per intestinal area.…”

“…Previous studies have reported changes in intestinal absorptive patterns and motility (Takano 1964), morphological changes in intestinal size, changes in the thickness of the tunica mucosa and muscularis (Firmansyah et al 1989a, Schoffen et al 2005, changes in the number of goblet cells (Hermes et al 2008b, Franco et al 2010, and variations in the amount and size of myenteric neurons (Santer and Conboy 1990, Araújo et al 2003, Natali et al 2003, Hermes et al 2008a in animals subjected to nutritional deprivation at different ages and stages of life.…”