Overfeeding-Induced Obesity in Spontaneously Hypertensive Rats: An Animal Model of the Human Metabolic Syndrome

Abstract

Background/Aims: The metabolic syndrome (MS) has become an epidemiological problem in Western countries. We developed a diet-induced obese rat model that mimics all the symptoms of MS in humans, but whose insulin resistance, hyperphagia and hyperleptinemia are caused by nutrition rather than genetic modifications. Methods: Spontaneously hypertensive rats (SHR) were allowed for 12 weeks to choose between a cafeteria diet (CD, 20.3 kJ/g) and standard rat chow (11.7 kJ/g). Controls received rat chow. Results: Body weight (BW) exceeded control levels when SHR were fed with CD. The increase in BW was attributed to enhanced energy intake. The abundance of abdominal fat as well as the plasma levels of leptin and triglycerides increased concomitant with glucose, insulin and C-peptide. This prediabetic condition was further confirmed by a markedly increased insulin response following glucose challenge and by impaired glucose utilization after insulin tolerance tests. Conclusion: Increases in food intake and BW despite hyperleptinemia indicate leptin resistance following CD feeding. CD-fed SHR feature leptin and insulin resistance, hypertension and obesity, thus mimicking the situation of MS patients. As such, our model is more suitable than the genetically modified rat models used to study human MS.

Effect of meat product with onion skin extract on мetabolic profile in SHR

“…These rats have increased body weight due to caloric exceed. Also they showed higher insulin and C-peptide level [12]. It is noteworthy that we had initially high glucose in the rats with genetically determined hypertension.…”

“…In above mentioned animal studies of carbohydrates overload for developing of metabolic syndrome different lipid profile results can be in part explained by rat strain, type of carbohydrates used and experiment design [12].…”

“…This rat strain was chosen because arterial hypertension is prevalent CVD in Ukraine and is one of key components of metabolic syndrome. To provoke metabolic disorders in animals carbohydrate or fat overload is usually used [10][11][12]. We choose carbohydrate overload, according to modern nutritional pattern of Ukrainian people with metabolic syndrome.…”

Effect of Angiotensin (1-7) on Heart Function in an Experimental Rat Model of Obesity

“…However, body weight, coronary flow to heart weight ratio and capillary to muscle fiber ratio were affected by CD and this CD-mediated effect regarding these parameters could be inhibited by Ang (1-7). First, the lack of cardiovascular effect of CD needs discussion: Others have described the development of hypertension following CD (e.g., Coatmellec-Taglioni et al, 2000;Muntzel et al, 2012;Steiner et al, 2013) and attributed this to increased sympathetic activity (Muntzel et al, 2012) or to the RAAS system (Miesel et al, 2010;Müller-Fielitz et al, 2014). Regarding the cafeteria diet, the authors used 2-20 weeks protocols, so that our protocol seems comparable.…”

“…Maybe that a longer time of CD-in the composition used by us-is needed to allow the cardiovascular effects to develop. Some of the authors (Miesel et al, 2010) used spontaneously hypertensive rats, which also may exhibit some differences in the blood pressure response. However, our data clearly show that there are only very moderate insignificant changes in the hearts performance, the isolated hearts characteristic, while there is a profibrotic effect in cardiac histology, which however, does not seem to be transduced to the functional level.…”