The prevalence of obesity and type II diabetes is increasing. Although exercise is widely accepted for prevention and treatment, evidence of resistance to exercise in patients with these diseases is also mounting. Muscle contraction during exercise stimulate cellular responses important for adaptation. These responses include the release of myokines and the subsequent increase in substrate metabolism. This study aimed to define a culture model for simulating exercise in human primary skeletal muscle cells. We hypothesized that chronic electric pulse stimulation (EPS) of human myotubes in vitro would emulate cellular and molecular responses to exercise observed in vivo. To define this model, we applied EPS to human myotubes for varied lengths of time and measured interleukin-6 (Il-6), peroxisome proliferator-activated receptor gamma coactivator 1- (PGC1-), superoxide dismutase 2 (SOD2), substrate metabolism, metabolic enzyme activity, heat stress markers, and pH. To recreate the inflammatory milieu observed in metabolic disease states we treated the myotubes with a low dose of 20 EU lipopolysaccharide (LPS). Following the 24-hour stimulation we observed significant increases in transcription of Il-6, PGC1-, and SOD2. Basal glucose and fatty acid oxidation were also markedly increased in the cells after EPS. Cells treated with LPS elicited a blunted transcriptional, metabolic, and enzymatic response to EPS. These findings suggest that EPS is a viable model for simulating the effects of exercise. Our observations also indicate that an inflammatory environment could play a role in interfering with the adaptations to exercise. / Ph. D. / The prevalence of obesity and type II diabetes is increasing. Although exercise is widely accepted for prevention and treatment, evidence of resistance to exercise in patients with these diseases is also mounting. Muscle contraction during exercise stimulate cellular responses important for adaptation. These responses include the release of myokines and the subsequent increase in substrate metabolism. This study aimed to define a culture model for simulating the effects of exercise in human primary skeletal muscle cells. We hypothesized that stimulating these cells with electric pulses (EPS) cultured m in vitro would simulate cellular and molecular responses to exercise. To define this model, we applied EPS to human skeletal muscle cells for varied lengths of time and measured transcription of interleukin-6 (Il-6), peroxisome proliferator-αctivated receptor gamma coactivator 1-α (PGC1-α), superoxide dismutase 2 (SOD2), substrate metabolism, metabolic enzyme activity, heat stress markers, and pH. To recreate the inflammatory status observed in metabolic disease states we treated the cells with a low dose of 20 endotoxin units (EU) lipopolysaccharide (LPS). Following the 24-hour stimulation we observed significant increases in transcription of Il-6, PGC1-α, and SOD2. Basal glucose and fatty acid oxidation were also markedly increased in the cells after EPS. Cells treated with LPS elicited a blunted transcriptional, metabolic, and enzymatic response to EPS. These findings suggest that EPS is a viable model of an in vitro exercise model. Our observations also indicate that an inflammatory environment could play a role in interfering with the adaptations to exercise.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/78235 |
| Date | 20 June 2017 |
| Creators | Harvey, Mordecai Micah |
| Contributors | Human Nutrition, Foods, and Exercise, Hulver, Matthew W., Frisard, Madlyn I., Davy, Kevin P., Grange, Robert W., Li, Liwu |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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