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Time‐dependent muscle‐specific protein oxidation in a mouse model of chronic hypoxia
Author(s) -
O'Halloran Ken,
Sheehan David,
Lewis Philip
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.719.2
Subject(s) - respiratory system , protein carbonylation , hypoxia (environmental) , chemistry , medicine , endocrinology , thiol , glutathione , biochemistry , oxygen , enzyme , organic chemistry
Respiratory muscle redox homeostasis is altered by chronic hypoxia (CH). Protein oxidation potentially contributes to respiratory muscle dysfunction in respiratory‐related diseases where hypoxia features. The objective of this study was to determine the type and extent of respiratory and limb muscle protein oxidation temporally in a mouse model of CH. C57/Bl6J mice were exposed to hypoxia (1, 3 and 6 weeks; 10% F i O 2 ) or normoxia. Following treatment, excised respiratory and limb muscles were homogenised and incubated with carbonyl‐ or thiol‐reactive fluorophores before gel electrophoresis and fluorescence scanning. Optical density (OD) of fluorescence was normalised to total protein, determined by colloidal coomassie staining. Diaphragm free‐thiol content increased ~9‐fold after 1 week of CH. By 6 weeks, both diaphragm and sternohyoid free‐thiol content were significantly decreased (40% and 80% decrease from control respectively; n=6–8 per group; P=0.0046 and P<0.0001, Student's unpaired t‐test) whereas there was a significant increase in the extensor digitorum longus (232%; P=0.0007) and in soleus (143%; P<0.0001). Diaphragm carbonyl content was unchanged after 1 week of CH, but was increased significantly by 3 weeks and was increased further again after 6 weeks. The extent of carbonylation was different between muscle groups. We conclude that CH exposure causes differential time‐dependent protein oxidation in respiratory and limb muscles.