Browsing by Author "Rios, Jaqueline Lourdes"

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    Exercise and dietary interventions in a rat model of metabolic knee osteoarthritis
    (2019-09-05) Rios, Jaqueline Lourdes; Herzog, Walter; Hart, David D.; Reimer, Raylene A.; Krawetz, Roman J.; Beier, Frank
    Osteoarthritis is a debilitating chronic disease which has no cure or effective treatment. If no changes are made in prevention and treatment, osteoarthritis will continue to represent a significant economic burden to patients and society. The goal of this thesis was to determine the effects of moderate aerobic exercise and prebiotic fibre supplementation on the onset and progression of the metabolic knee osteoarthritis phenotype in rats exposed to a high-fat/high-sucrose diet. This study was divided into three phases. Phase 1: we evaluated the effects of a 12-week aerobic exercise program of varying duration on healthy rat knee cartilage. We determined that moderate, high and extra-high duration treadmill exercise has no detrimental effects on knee joint health, function and integrity. Therefore, we concluded that treadmill exercise at any tested duration was a safe exercise for rats in terms of knee osteoarthritis-like damage, and therefore, could be used as a safe exercise intervention in a pre-clinical rat model of knee osteoarthritis. Phase 2: we evaluated the effects of moderate aerobic exercise, prebiotic fibre supplementation, and the combination of exercise and fibre over a 12-week intervention in rats exposed to a high-fat/high-sucrose diet that has been shown to cause knee joint damage. Our findings indicated that prebiotic fibre and aerobic exercise prevented knee joint damage in this model. Phase 3: we evaluated if the damaging effects of the high-fat/high-sucrose diet could be delayed/reversed. We determined that neither prebiotic fibre supplementation nor aerobic exercise were able to stop the progression of existing knee osteoarthritis-like damage induced by a high-fat/high-sucrose diet. In summary, this thesis provides insight into two different approaches to prevent the development of metabolic osteoarthritis phenotype. However, the studies presented in this thesis were not able to show an effective way to stop the progression of the disease.
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    The mechanical and biochemical properties of tail tendon in a rat model of obesity: effect of moderate exercise and prebiotic fibre supplementation
    (2019-05-09) Rios, Jaqueline Lourdes; Ko, Loretta; Joumaa, Venus; Liu, Shuyue; Diefenthaeler, Fernando; Sawatsky, Andrew; Hart, David A.; Reimer, Raylene A.; Herzog, Walter
    The worldwide trajectory of increasing obesity rates is a major health problem precipitating a rise in the prevalence of a variety of co-morbidities and chronic diseases. Tendinopathy, in weight and non-weight bearing tendons, in individuals with overweight or obesity has been linked to metabolic dysfunction resulting from obesity. Exercise and dietary fibre supplementation (DFS) are common countermeasures to combat obesity and therefore it seems reasonable to assume that they might protect tendons from structural and mechanical damage in a diet-induced obesity (DIO) model. The purpose of this study was to determine the effects of a DIO, DIO combined with moderate exercise, DIO combined with DFS (prebiotic oligofructose), and DIO combined with moderate exercise and DFS on the mechanical and biochemical properties of the rat tail tendon. Twenty-four male Sprague-Dawley rats, fed a high-fat/high-sucrose diet were randomized into a sedentary, a moderate exercise, a DFS, or a moderate exercise combined with DFS group for 12 weeks. Additionally, six lean age-matched animals were included as a sedentary control group. DIO in combination with exercise alone and with exercise and DFS reduced the Young's Modulus but not the collagen content of the rat tail tendons compared to lean control animals. However, no differences in the mechanical and biochemical properties of the rat tail tendon were detected between the DIO and the lean control group, suggesting that DIO by itself did not impact the tail tendon. It seems that longer DIO exposure periods may be needed to develop overt differences in our DIO model.
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    Protective effect of prebiotic and exercise intervention on knee health in a rat model of diet-induced obesity
    (2019-03-07) Rios, Jaqueline Lourdes; Bomhof, Marc R.; Reimer, Raylene A.; Hart, David A.; Collins, Kelsey H.; Herzog, Walter
    Obesity, and associated metabolic syndrome, have been identified as primary risk factors for the development of knee osteoarthritis (OA), representing nearly 60% of the OA patient population. In this study, we sought to determine the effects of prebiotic fibre supplementation, aerobic exercise, and the combination of the two interventions, on the development of metabolic knee osteoarthritis in a high-fat/high-sucrose (HFS) diet-induced rat model of obesity. Twelve-week-old male Sprague-Dawley rats were randomized into five groups: a non-exercising control group fed a standard chow diet, a non-exercising group fed a HFS diet, a non-exercising group fed a HFS diet combined with prebiotic fibre supplement, an exercise group fed a HFS diet, and an exercise group fed a HFS diet combined with prebiotic fibre supplement. Outcome measures included knee joint damage, percent body fat, insulin sensitivity, serum lipid profile, serum endotoxin, serum and synovial fluid cytokines and adipokines, and cecal microbiota. Prebiotic fibre supplementation, aerobic exercise, and the combination of the two interventions completely prevented knee joint damage that is otherwise observed in this rat model of obesity. Prevention of knee damage was associated with a normalization of insulin resistance, leptin levels, dyslipidemia, gut microbiota, and endotoxemia in the HFS-fed rats.