About OpenKnowledge@NAU | For NAU Authors

Glutathione reductase regulation in mouse skeletal muscle stimulated ex-vivo: a pilot study

Hays, Lauren Elizabeth (2021) Glutathione reductase regulation in mouse skeletal muscle stimulated ex-vivo: a pilot study. Masters thesis, Northern Arizona University.

[thumbnail of Hays_2021_glutathione_reductase_regulation_mouse_skeletal_muscle_stimu.pdf] Text
Hays_2021_glutathione_reductase_regulation_mouse_skeletal_muscle_stimu.pdf - Published Version
Restricted to Repository staff only

Download (986kB) | Request a copy


Muscle contraction induces oxidant production that matches the magnitude, duration, and intensity of the contractile stimulus, however the effects on redox-sensitive proteins are still not well understood. In the present study, we aimed to measure the redox signaling response to skeletal muscle stimulation in an ex vivo model. We hypothesized that muscle stimulation would induce an increase in oxidation of the antioxidant protein glutathione reductase (GSR). Extensor digitorum longus (EDL) muscles were removed from mice and one muscle was stimulated ex vivo. The stimulated muscle received thirty isometric tetanic stimulations (500 ms train, 0.8 ms pulse duration, 140 Hz) delivered with 500 ms breaks in between each tetanus. This stimulation loop was delivered ten times for a total of 300 tetanic stimulations. On average, the maximum force a tetanic stimulation produced decreased by 79% percent following the protocol, confirming that the muscle was fatigued. The control EDL muscle was placed in an oxygenated Krebs bath for an equal amount of time, but did not undergo stimulation. Following the experiment, both muscles were flash frozen in liquid nitrogen, stored at -80 °C and later homogenized in reducing and non-reducing buffer. Levels of GSR were measured via western blotting. There were no significant changes in overall protein abundance. However, the amount of GSR located at 55kDa, the expected molecular weight, showed a trend increasing in response to stimulation p=0.0754. A trend was also observed toward increasing GSR with stimulation at the elevated (>100kDa) molecular weight (p=0.0711). An unexpected result of the study was the significant effect of animal as a random variable nested within sex on the data (p=<0.0001). We investigated the effects of order of the experiments, age, body weight, and sex on the inter-animal variability, however no clear trends emerged. While these results require further investigation to fully understand the patterns of oligomerization of GSR in skeletal muscle tissue, as far as we are aware these are the first data to describe oxidation/oligomerization of GSR. It is still unclear how oxidation/oligomerization affects enzyme function, turnover, or localization of GSR and further work is necessary.

Item Type: Thesis (Masters)
Publisher’s Statement: © Copyright is held by the author. Digital access to this material is made possible by the Cline Library, Northern Arizona University. Further transmission, reproduction or presentation of protected items is prohibited except with permission of the author.
Keywords: ex vivo ; extensor digitorum longus; glutathione reductase; mouse; muscle fatigue; redox
Subjects: Q Science > QL Zoology
MeSH Subjects: A Anatomy > A02 Musculoskeletal System
NAU Depositing Author Academic Status: Student
Department/Unit: Graduate College > Theses and Dissertations
College of the Environment, Forestry, and Natural Sciences > Biological Sciences
Date Deposited: 09 Feb 2022 17:25
Last Modified: 09 Feb 2022 17:25
URI: https://openknowledge.nau.edu/id/eprint/5676

Actions (login required)

IR Staff Record View IR Staff Record View


Downloads per month over past year