Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Date of Graduation

Summer 2018

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Department of Kinesiology

Advisor(s)

Nicholas D. Luden

Michael J. Saunders

Christopher J. Womack

Abstract

Introduction: MicroRNA (miRNA) are small, non-coding RNA that act post-transcriptionally to regulate gene expression. miRNA levels are modulated by acute aerobic exercise, yet little is known about how miRNA levels may change in response to high-intensity interval exercise. Further, almost nothing is known about the impact of post-exercise nutrition (carbohydrate and/or protein) on miRNA levels. Thus, the purpose of this study is to examine the effects of high-intensity interval cycling and different post-exercise nutrients on ci-miRNA levels. Methods: Nine recreationally active males (age 21.9 ± 2.0yrs; VO2max 49.6 ± 4.0mL/kg/min) competed three trials, each including identical exercise protocols. Protocol involved two Wingate tests separated by four sets of high-intensity (3 minutes @ 90% Wmax separated by 1 minute @ 50% Wmax) intervals, along with warm-up and cooldown. Finger stick and venous blood samples were collected pre- and up to four hours post-exercise. Additionally, a different nutrition treatment (i.e. carbohydrate, carbohydrate + protein, or control) was administered immediately post-exercise. Serum samples were analyzed for content of twelve target miRNA (miR-1, -21, -126, -133a, -146a, -150, -206, -210, -221, -222, -486, and -499). miRNA levels were expressed as fold changes relative to baseline of 1 and paired-samples t-tests and post hoc two-way, repeated measures ANOVAs were used to detect changes in miRNA levels across chosen timepoints and treatments. Results: miR-210 and miR-486 were unaffected by exercise at any timepoints and all remaining targets were either unchanged or upregulated immediately post-exercise. Most targets (except miR-1) were returned to baseline at four-hours post-exercise. Nutrition only affected miR-150, downregulating it at one-hour post-exercise. Post hoc analysis revealed a main effect for time for all targets immediately post-exercise. Further, a main effect for time was observed one-hour post-exercise for miR-1 and miR-210 and at four hours pos-exercise for miR-210 and mIR-146a. Conclusion: High-intensity cycling impacted miRNA implicated in skeletal and cardiac phenotype, angiogenesis, and inflammation, though post-exercise nutrition was inconsequential except for miR-150. It is currently unknown the extent to which intracellular miRNA activity may be reflected in circulation, thus further work is needed to study how nutrition may influence miRNA response to exercise.

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