Examining the effects of diet on muscle health in a female diet-induced obesity rat model
Date
2024-01-24
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Abstract
Worldwide obesity has tripled in the last 50 years as energy dense food and low activity levels common in westernized societies have become the norm. The excess fat associated with obesity, puts significant stress on the body’s metabolic pathways, leading to many noncommunicable diseases, including certain musculoskeletal (MSK) disorders, such as sarcopenic obesity. Sarcopenic obesity is the loss of muscle mass and strength coupled with an excess fat mass and fatty infiltrations into the muscle tissue called myosteatosis. Fortunately, obesity is modifiable through diet interventions as it has been previously shown that prebiotic fibre supplementation can decrease body fat percentage and improve metabolic health. However, there are a lack of studies to date that look at the effect of a prebiotic fibre on compromised muscle integrity as a consequence of obesity. To study fat infiltration in muscle tissue, a diet-induced obesity model was developed in male Sprague-Dawley rats, however, female animals were neglected to be considered. The purpose of this thesis was to (1) establish a model of diet-induced obesity in female Sprague-Dawley rats and compare changes in muscle integrity to the already existing male model and (2) determine the effect of a 3-week delayed prebiotic fibre supplement on intramuscular fat infiltration. Through a combination of histological staining techniques and measures of metabolic syndrome and inflammatory cytokines, we quantified intramuscular fat, fibrosis, local inflammation, metabolic dysfunction, and systemic inflammation. It was determined that the diet-induced obesity model in female Sprague-Dawley rats is a viable model and that sex-dependent differences in intramuscular fat infiltration exist. We also observed that the 3-week delayed prebiotic fibre diet supplement was able to protect against certain consequences of obesity such as increased blood triglycerides and fat infiltration in the vastus lateralis, but not others such as fat infiltration in the soleus and systemic inflammation associated with metabolic endotoxemia.
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Keywords
Muscle, Sarcopenia, Obesity, Metabolic syndrome, Metabolic endotoxemia, Prebiotic fibre, High fat/high sucrose diet, Nutrition
Citation
Smith, H. E. (2024). Examining the effects of diet on muscle health in a female diet-induced obesity rat model (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.