Dietary selenium augments sarcoplasmic calcium release and mechanical performance in mice

Dóra Bodnár; Olga Ruzsnavszky; Tamás Oláh; Beatrix Dienes; Ildikó Balatoni; Éva Ungvári; Ilona Benkő; Beáta Babka; József Prokisch; László Csernoch; Péter Szentesi

doi:10.1186/s12986-016-0134-6

Dietary selenium augments sarcoplasmic calcium release and mechanical performance in mice

Nutr Metab (Lond). 2016 Nov 3:13:76. doi: 10.1186/s12986-016-0134-6. eCollection 2016.

Affiliations

¹ Department of Physiology, Faculty of Medicine, University of Debrecen, P.O. Box 400, H-4002 Debrecen, Hungary.
² Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
³ Institute of Animal Science, Biotechnology and Nature, Faculty of the Agricultural and Food Sciences and Environmental Management, University of Debrecen, Debrecen, Hungary.

Abstract

Background: As an essential trace element selenium plays a significant role in many physiological functions of the organs. It is found within muscles as selenocystein in selenoprotein N, which is involved in redox-modulated calcium homeostasis and in protection against oxidative stress.

Methods: The effects of two different selenium compounds (selenate and NanoSe in 0.5 and 5 ppm concentration for two weeks) on muscle properties of mice were examined by measuring in vivo muscle performance, in vitro force in soleus (SOL) and extensor digitorum longus (EDL) muscles and changes in intracellular Ca²⁺ concentration in single fibers from flexor digitorum brevis (FDB) muscle.. Western-blot analysis on muscle lysates of EDL and SOL were used to measure the selenoprotein N expression. Control mice received 0.3 ppm Se.

Results: While the grip force did not change, 5 ppm selenium diets significantly increased the speed of voluntary running and the daily distance covered. Both forms of selenium increased significantly the amplitude of single twitches in EDL and SOL muscle in a concentration dependent manner. Selenate increased fatigue resistance in SOL. The amplitude of the calcium transients evoked by KCl depolarization increased significantly from the control of 343 ± 44 nM to 671 ± 51 nM in the presence of 0.5 ppm selenate in FDB fibers. In parallel, the rate of calcium release during short depolarizations increased significantly from 28.4 ± 2.2 to 45.5 ± 3.8 and 52.1 ± 1.9 μM/ms in the presence of 0.5 ppm NanoSe and selenate, respectively. In 0.5 ppm concentration both selenium compounds increased significantly the selenoprotein N expression only in EDL muscle.

Conclusions: Selenium supplementation augments calcium release from the sarcoplasmic reticulum thus improves skeletal muscle performance. These effects are accompanied by the increased selenoprotein N expression in the muscles which could result in increased oxidative stress tolerance in case of long lasting contraction.

Keywords: Force; Intracellular calcium concentration; Selenium; Selenoprotein; Skeletal muscle.