Rodent Models of Obesity and Diabetes

Abstract

Genetically modified animals are a widely used tool in biomedical research, since it allows modeling diseases, studying their pathological conditions and identifying and validating new drugs. One of the most common diseases studied in recent years is metabolic disorders resulting from abnormalities in enzyme systems involved in the intermediary metabolism of living organisms with a heavy impact on society. To understand the physiological mechanisms underlying these disorders, animal models, currently the transgenic type, have been employed. It is important to emphasize that there are various metabolic disorders that are not only congenital but can be acquired or a coexistence of both types. The aim of this chapter, therefore, is to describe the most commonly used rodent models focusing mainly on global emerging pathologies, obesity, diabetes and metabolic syndrome.

Obesity Rodent Models Applied to Research with Food Products and Natural Compounds

“…Diet-induced obesity (DIO) rodent models are achieved by exposing rats and mice to specific diets that induce obesity, thereby reproducing dietary imbalances that are often the main cause of obesity in humans [13,20,52,53]. The main advantage of diets is that they can be standardized and control the nutrient percentages.…”

“…There are a variety of diets that can be used for this purpose, such as high-fat diets (HFD), high-sugar diets (HSD), and high-sugar and high-fat (HSHF) diets, known as Western diets [16]. The HFD-induced obesity mouse model is one of the most used to understand the relationship between hyperlipidemic diets and the pathophysiology of obesity [52]. Within mouse strains, there are some more susceptible to DIO than others [13,54]; for example, the inbred C57BL/6 mouse strain is highly susceptible in contrast to SWR/J, A/J and CAST/Ei mouse strains, which tend to be resistant to these diets.…”

“…Within mouse strains, there are some more susceptible to DIO than others [13,54]; for example, the inbred C57BL/6 mouse strain is highly susceptible in contrast to SWR/J, A/J and CAST/Ei mouse strains, which tend to be resistant to these diets. In fact, the C57BL/6J mouse strain is the most used since when they are fed with HFD, these animals develop characteristics similar to humans with complex metabolic syndrome, such as obesity, high fat accumulation, insulin resistance, hyperglycemia, hyperlipidemia, hypertension, non-alcoholic fatty liver disease, and endothelium damage associated with cardiovascular diseases [18,20,52,55,56]. Some rat strains can also be used as models of HFD-induced obesity, such as the outbred Sprague Dawley, Wistar, or Long Evans rats [14].…”

Rodent models of metabolic disorders: considerations for use in studies of neonatal programming

“…Studies have implicated not just genetic variations like polymorphisms and mutations of certain genes, but also prenatal and postnatal environmental factors, that influence the expression of the genes responsible for the metabolism of carbohydrates and lipids. (2) The term "developmental programming" describes adaptive phenotypic changes that occur in later life following environmental exposure to certain factors, termed "stressors" or "cues", at critical periods of early life. The intrauterine and neonatal life represent critical and sensitive periods of programming for cellular metabolism.…”

“…These and other metabolic diseases arise due to one or more abnormalities in the components of cellular metabolism. Studies have implicated not only genetic variations like polymorphisms and mutations of certain genes but also prenatal and postnatal environmental factors that influence the expression of the genes responsible for the metabolism of carbohydrates and lipids (2) .…”