Dietary selenium augments sarcoplasmic calcium release and mechanical performance in mice

Abstract

BackgroundAs 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.MethodsThe 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.ResultsWhile 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.ConclusionsSelenium 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.Electronic supplementary materialThe online version of this article (doi:10.1186/s12986-016-0134-6) contains supplementary material, which is available to authorized users.

Improved Calcium Homeostasis and Force by Selenium Treatment and Training in Aged Mouse Skeletal Muscle

“…We also found beneficial effects of selenium on both in vivo and in vitro muscle function and, in addition, on calcium homeostasis in aged mice. The fact that selenium has similar positive effects on muscles from young 9 and aged animals (this study) underlines its potential application in the treatment of sarcopenia.…”

“…i) Since RyR1 is very sensitive to oxidative changes, its accommodation to oxidative stress through conditioning with lifelong training could improve the calcium channel functions as demonstrated by the decreased degradation of RyR1 in trained animals. ii) As RyR1 degradation was not reduced in selenium supplemented aged animals, nevertheless selenium as an antioxidant increased muscle performance both in young 9 and aged animals (this study), RyR1 independent pathway(s) should also underlie the observed effects.…”

“…In our previous work on young mice we have shown that selenium supplementation increases calcium release from the sarcoplasmic reticulum (SR) and so improves in vivo and in vitro skeletal muscle performance. These effects were accompanied by the elevated level of Selenoprotein N in the muscles, which could result in enhanced oxidative stress tolerance during long lasting contractions 9 . As the Selenoprotein N content of the muscle was shown decrease with age 10 , it was of interest to see if long lasting selenium supplementation would reverse this decline and, consequently, improve muscle performance in aged animals.…”

“…Black vertical and horizontal lines indicate the merging border between standard (std) and the bands, and the bands detected with different exposition times, respectively. (2020) 10:1707 | https://doi.org/10.1038/s41598-020-58500-x www.nature.com/scientificreports www.nature.com/scientificreports/ performance in young mice 9 . A two week selenium treatment improved maximal voluntary running speed, and fatigue resistance.…”

Improved Tetanic Force and Mitochondrial Calcium Homeostasis by Astaxanthin Treatment in Mouse Skeletal Muscle

“…Muscle contractions were measured as described previously [46]. Briefly, EDL muscles were placed horizontally in an experimental chamber.…”