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

João Paulo F Schoffen,Eduardo J.A Araújo,Fernando A Vicentini,Maria M.D Pedrosa,Carolina G Marcelino,Maria R.M Natali

doi:10.1590/0001-3765201420140163

Abstract

The effects of food restriction (FR) on the morphoquantitative aspects of the wall and myenteric neurons of the proximal colon in adult rats were analysed. FR was imposed by duplication of the experimental brood size in relation to the control brood during lactation. The FR group received a 50% reduction of food from weaning until 90 days of age. Samples of the colon underwent histological processing to morphometrically analyze the crypts, muscularis mucosae, tunica mucosa, and muscularis externa. We determined the number of goblet cells and serotoninergic enteroendocrine cells, and morphoquantitatively studied the myenteric neuronal population. FR caused hypertrophy in the tunica mucosa, increase in crypt depth and in the muscular layer of the mucosa, a decrease in the thickness of the tunica muscularis and in the number of goblet cells and an increase in serotoninergic cells. A higher neuronal density in the ganglia and a reduction of the cell profile area were observed in the FR group. FR imposed since lactation led to hypertrophy of the tunica mucosa, a reduction of neutral mucin production, atrophy of the tunica muscularis, and an increase in the survival neuronal in adult rats, attributable to an increase in the number of serotoninergic enteroendocrine cells in mucosa.

Highlights

The food restriction (FR) protocol used in the present study proved the effectiveness of this model in Wistar rats
The lower intake of nutrients led to a targeting of these nutrients to organs that are considered vital to the survival of these animals, causing the still-growing colon structure to adapt to low nutrient availability
A reduction of the dimensions of the large intestine caused by a restricted food supply (Firmansyah et al 1989a) or restricted content of protein in the diet (Sant'Ana et al 1997, Castelucci et al 2002, Araújo et al 2003, Schoffen et al 2005, Hermes et al 2008a,b) was frequently observed

Summary

Introduction

The large intestine is the last portion of the gastrointestinal tract (GIT) and plays a key role in hydroelectrolytic balance, in addition to participating in the formation and elimination ofThe colonic mucosa is lined with a single layer of cylindrical epithelial cells with different cell types distributed in deep intestinal crypts, including enterocytes involved in the fragmentation and final absorption of nutrients, stem cells for rene wing the epithelium, mucus-secreting goblet cells, hormone-secreting enteroendocrine cells (Ovalle and Nahirney 2008), and undifferentiated cells.The mucus that covers the epithelium represents the first line of intestinal mucosal defense against the invasion of antigens and bacteria that are present in the colonic lumen (Corfield et al 2000, Mello et al 2012). The detection and response to components of the intestinal lumen involve intrinsic and extrinsic primary afferent neurons and the activation of reflex pathways Such reflexes coordinate intestinal secretion and motility, resulting in a balance between the amount of nutrients digested and the absorption capacity of the intestine (Raybould 2002). Enteroendocrine cells are specialized cells that act as sensory transducers in the epithelium of the intestinal mucosa by secreting serotonin (5-hydroxytryptamine [5HT]), an important neuroendocrine transmitter of the GIT (Gershon 2013). Changes in these cells or signaling mediated by 5-HT may result in intestinal dysmotility, visceral hypersensitivity, and secretomotor abnormalities (Crowell 2004)

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