Gastrointestinal morphofunctional changes in experimental obesity models

Obesity is a global health problem whose incidence is steadily increasing. Modern lifestyles, characterized by changing dietary preferences and low levels of physical activity, are key factors in the development of obesity and overweight. Obesity increases the risk of numerous gastrointestinal (GI) diseases, such as gastroesophageal reflux disease, inflammatory bowel disease, functional digestive disorders, and others. The pathogenesis of these conditions includes chronic low-grade inflammation, increased intestinal barrier permeability, and changes in the intestinal microflora. The purpose of this article is to describe and systematize high-calorie diets and to study the morphological and pathophysiological mechanisms by which these diets influence the gastrointestinal tract. This review examines the main types of diets used to model obesity in laboratory animals: high-fat, high-carbohydrate, with a choice of fats or carbohydrates, combined (“cafeteria diet”, “Western diet”), and models of psychogenic overeating. Histological features of the gastrointestinal tract wall of obese rats are represented by changes in the mucosa (a decrease in the number of PAS-positive goblet cells) and the lamina propria (an increase in the number of neutrophils, lymphocytes, macrophages, and collagen fibers). In addition, increased concentrations of IL-1β, IL-6, IL-8, TNF and monocyte chemotactic protein (MCP-1), and malondialdehyde (MDA) were detected in the colon wall. Obesity and excess body weight have been shown to impact structural components of the nervous system (hyperactivation of enteric ganglia, disruption of the autonomic nervous system, etc.), leading to impaired gastrointestinal motility.

Experimental studies demonstrate that high-calorie diets alter the histological characteristics and motility of the gastrointestinal tract in laboratory animals, causing structural damage and disruption of innervation of the digestive organs. This indicates the need for further research to identify the mechanisms underlying the development of obesity complications and develop effective preventive measures.

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