Title

Voluntary wheel running prevents the acidosis-induced decrease in skeletal muscle mitochondrial reactive oxygen species emission

Document Type

Journal Article

Publication Title

The FASEB Journal

ISSN

1530-6860

Volume

33

Issue

4

First Page

4996

Last Page

5004

PubMed ID

30596520

Publisher

Federation of American Societies for Experimental Biology

School

School of Medical and Health Sciences

Comments

Originally published as: Hedges, C. P., Bishop, D. J., & Hickey, A. J. R. (2019). Voluntary wheel running prevents the acidosis-induced decrease in skeletal muscle mitochondrial reactive oxygen species emission. The FASEB Journal, 33(4), 4996–5004. Original publication available here

Abstract

Decreases in pH (acidosis) in vitro can alter skeletal muscle mitochondrial function [respiration and reactive oxygen species (ROS) emission]. However, because skeletal muscles readily adapt to exercise, the effects of acidosis may be different on sedentary vs. trained muscle. The aim of this work was to compare the effects of pH on skeletal muscle mitochondrial function between sedentary vs. exercise-trained male Sprague-Dawley rats ( n = 10 in each cohort). Rates of mitochondrial respiration and ROS emission were determined from the soleus muscle of both cohorts over a physiologic range of pH values (pH 6.2-7.1). Exercise-trained rats had 14% higher mean muscle buffering capacities; 46 and 40% greater enzyme activity of citrate synthase and lactate dehydrogenase, respectively; and greater activity of respiratory complexes I-IV. ADP-stimulated respiration with complex I and II substrates was ∼25% greater in exercise-trained rats but was unaffected by pH in either cohort. In both cohorts, lowering pH decreased respiration only in complex I- and complex II-supported nonphosphorylating (leak) state. However, as pH decreased, ROS emissions in complex I- and complex II-supported leak state decreased only in sedentary rats; in exercise-trained rats, ROS emissions in this state remained constant. We hypothesize that this effect may result from modulation at complex III, which declined 47% per unit pH in sedentary rats, in comparison to 23% in exercise-trained rats. Taken together, these data suggest that pH regulates mitochondrial respiratory complexes and that exercise training can decrease the effects of pH on skeletal muscle mitochondrial function.-Hedges, C. P., Bishop, D. J., Hickey, A. J. R. Voluntary wheel running prevents the acidosis-induced decrease in skeletal muscle mitochondrial reactive oxygen species emission.

DOI

10.1096/fj.201801870R

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