Abstract
Aim: The aim of this study was to determine whether a 14-day trekking expeditions, in high altitude hypoxic environment, triggers redox disturbance at the level of satellite cells (adult stem cells) in young women.Methods: We collected muscle biopsies from Vastus Lateralis muscle for both single fiber analysis and satellite cells isolation. The samples collected before (PRE-Hypoxia) and after (POST-Hypoxia) the trekking in the Himalayas were compared. Satellite cells were investigated for oxidative stress (oxidant production, antioxidant enzyme activity, and lipid damage), mitochondrial potential variation, gene profile of HIF, and myogenic transcription factors (Pax7, MyoD, myogenin), and miRNA expression (miR-1, miR-133, miR-206).Results: The nuclear domain analysis showed a significant fusion and consequent reduction of the Pax7+ satellite cells in the single mature fibers. The POST-Hypoxia myoblasts obtained by two out of six volunteers showed high superoxide anion production and lipid peroxidation along with impaired dismutase and catalase and mitochondrial potential. The transcription profile and miRNA expression were different for oxidized and non-oxidized cells.Conclusions: The present study supports the phenomenon of hypobaric-hypoxia-induced oxidative stress and its role in the impairment of the regenerative capacity of satellite cells derived from the V. Lateralis muscle of young adult female subjects.
Highlights
The hypobaric hypoxia created by environmental conditions as during high altitude exposure, provides a strenuous oxygen supply restriction that affects human skeletal muscle, and leads to its specific adaptation
We enrolled in the Laboratory of Functional Evaluation seven healthy sedentary female subjects (#1–7) of childbearing age who were generally used to a sedentary life-style to serve as subjects to the study known as GOKYO KHUMBU/AMA DABLAM TREK 2012, carried out during the same expedition
We evaluated the following genes: paired box (Pax) 7 (#4331182, Hs 00242962_m1); myogenic differentiation (MyoD) 1 (#4331182, Hs 00159528_m1), myogenin (#4331182, Hs 01072232 GEX per-design_m1), and hypoxia-inducible factor (HIF; #4331182, Hs00153153_m)
Summary
The hypobaric hypoxia created by environmental conditions as during high altitude exposure, provides a strenuous oxygen supply restriction that affects human skeletal muscle, and leads to its specific adaptation. The skeletal muscle tissue remodeling is due to the satellite cells, adult stem cells, that upon activation are able to fuse with existing fibers, or to form new ones. Once activated, these cells proliferate (myoblasts), and differentiate (myotubes) rebuilding the muscle tissue (Ceafalan et al, 2014; Verdijk, 2014; Verdijk et al, 2014). This process, named myogenesis, occurs both in vivo and in vitro conditions
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