Research Article: Is the colon mucosa affected by ten days of gastric restriction in an animal model?1

Date Published: August 19, 2019

Publisher: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia

Author(s): Flávia Emi Akamatsu, Luiz Gustavo Fontes, Ana Maria Itezerote, Samir Saleh, Walcy Paganelli Rosolia Teodoro, Everson Artifon, Flávio Hojaij, Mauro Andrade, José Aires Pereira, Carlos Augusto Real Martinez, Alfredo Luiz Jacomo.


To identify whether the colon mucosa is affected by ten days of gastric restriction in an animal model.

An experimental model of gastric restriction was devised using rats. The animals were submitted to surgical gastrostomy, and a cylindrical loofah was inserted into the stomach. We studied 30 adult male Wistar rats divided into three groups: the stomach restriction group (R10); the sham group (S10), which underwent the same procedure except for the loofah insertion; and the control group (C10). The expression of neutral and acid mucins was evaluated using histochemical techniques. Goblet cells and protein content were compared between groups using generalized estimation equations (GEEs). Bonferroni’s multiple comparison was applied to identify differences between the groups. All tests considered a 5% significance level.

There was an increased expression of neutral mucins, acid mucins and goblet cells in the R10 group. Collagen was also enhanced in the R10 group.

The colon mucosa is affected by ten days of gastric restriction in an animal model, increasing neutral mucins, acid mucins and collagen content with trophic maintenance.

Partial Text

Obesity is a global epidemic1, and in adulthood, it is a major risk factor for the world’s leading causes of poor health and early death, including cardiovascular disease, several common cancers, diabetes and osteoarthritis2. The burden of disease generated from the high prevalence and consequences of obesity makes it a true global public health concern3. The only proven long-term treatment for severe obesity on a population level is the surgical modification of the gastrointestinal anatomy to induce weight loss, termed bariatric surgery4. Bariatric surgery, also called weight loss surgery or metabolic surgery, was introduced 50 years ago to provide drastic weight loss in morbidly obese patients5,6, and its use is currently increasing to treat patients with high adiposity, or occasionally for metabolic benefits7. The most successful types of bariatric surgery involve limiting the absorption of nutrients (malabsorption), reducing the size of the stomach to decrease the total nutrient intake (restriction), and reducing hunger and satiety by altering gut hormones (metabolic)3. Sleeve gastrectomy (SG), gastric bypass, gastric banding, and gastric plication (GP) are the most common procedures used to treat obesity8. However, recent studies have suggested serious complications that may result from weight reduction surgery, such as nutritional deficiencies9-13, the acceleration of nephropathy14, modification of the hippocampus cytoarchitecture15, changes in gene expression for subcutaneous fat and arcuate hypothalamic nucleus16and modifications in bone metabolism, accelerating the process of osteoporosis17. A body weight loss of 15% or more is associated with the loss of 20% of the body’s protein18. Recently, authors have reported constipation after bariatric surgery with diet, due to decreased bowel motility and prolonged bowel movement19. Restrictive diets and bariatric surgery related to nutrient deficiency rather than weight loss surgery reduce the microbial abundance and promote changes in the microbial composition that could have long-term, detrimental effects on the colon20. Goblet cells reside throughout the length of the small and large intestine and are responsible for the production and maintenance of the protective mucus blanket by synthesizing and secreting high-molecular-weight glycoproteins known as mucins. The tissue content and pattern of mucin expression in goblet cells change in patients with colorectal cancer, ulcerative colitis, intestinal infections, inflammatory bowel disease (IBD), cystic fibrosis (CF), and diversion colitis21-23. Disruption in the intestinal homeostasis results in a defective mucus barrier with increased permeability, which results in inflammation and injury of the intestinal mucosal cells24,25. Studies in experimental models have demonstrated that a deficiency in the supply of short-chain fatty acids (SCFAs) to the colon, devoid of transit, can modify proteins related to the intercellular junction systems, allowing the development of exclusion colitis22,26,27. SCFAs influence colonic health through various mechanisms. In vitro and ex vivo studies have shown that SCFAs have anti-inflammatory and anticarcinogenic effects, play an important role in maintaining metabolic homeostasis in colonocytes, and protect colonocytes from external harm28,29.

The statistical analysis showed that the weight of the restricted group decreased significantly (by 9%) in the first three days, and then increased (by 6.2% of the weight of the third day), which was conserved until the tenth day. Up to the 10th day there was a loss of approximately 4% of the initial weight. The weight of the sham group increased significantly from the first day to the tenth day, with an increase of 5.2% of the initial weight. The weight of the control group increased significantly from the first day to the tenth day, with an increase of 11% of the initial weight (Fig. 1).

Experimental bariatric surgery was performed to prevent weight gain. Studies in animals have shown that groups of rats or mice often gain weight over the observation period of a study36, and we consider this model to be efficient for experimental gastric restriction. Not only was weight gain prevented in the restrict group, but weight was lost in 10 days; a total of 4% of the initial weight. The control and sham groups gained weight over the 10-day study period; 11% and 5.2%, respectively, of the initial weight gained.

The colon mucosa is affected by ten days of gastric restriction. In an animal model of inflammatory situations, dietary restriction can promote mucin synthesis, equilibrate the gut microbiota, and thus favor colonic protection and mucosal healing. Trophism is conserved with 10 days of gastric restriction.




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