Docosahexaenoic acid (DHA) injection in spinal cord transection stimulates Na⁺,K⁺-ATPase in skeletal muscle via β 1 subunit.
Spinal cord injuries (SCI) induce a loss of skeletal muscle mass and functional capacity. The muscle excitability and contractility depend on the plasma membrane potential, regulated by transmembrane ion gradients, and thus necessarily on the Na⁺,K⁺-ATPase activity. The aim of this work was to evaluate the consequences of a spinal cord transection (SCT) on the skeletal muscle Na⁺,K⁺-ATPase and the impact of collateral GlyceroPhosphoLipids enriched in DocosaHexaenoic Acid (GPL-DHA) administration. The Na⁺,K⁺-ATPase activity and membrane expression of Na⁺,K⁺-ATPase α1, α2 and β1 isoforms were assessed by K⁺-stimulated paranitrophenyl phosphatase (pNPPase) measurements and Western Blotting, respectively. The results show that spinal cord transection increased significantly (p<0.05) Na⁺,K⁺-ATPase activity in muscle by 25% and decreased the amounts of α1 isoform and α2 isoform expressions by 50% (p<0.05) respectively compared to controls. The results also show that early injection of GPL-DHA after SCT decreases in membrane skeletal muscle the α1 and α2 isoforms expression but increases the membrane Na⁺,K⁺-ATPase activity. This treament partially restores the membrane expression of the β1 subunit of the Na⁺,K⁺-ATPase. These data suggest that the increase of β1 subunit expression is probably the main trigger to the membrane Na⁺,K⁺-ATPase activation following a trans-synaptic denervation.
Universit&eacute; du Sud Toulon&mdash;Var Équipe de Biologie Mol&eacute;culaire Marine, PROTÉE La Garde France mmaixent&commat;gmail.com.
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Maixent
Universit&eacute; de Poitiers & CHU la Mil&eacute;terie NSERM U927, Facult&eacute; de M&eacute;decine Poitiers France.
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Fares
Universit&eacute; de Poitiers & CHU la Mil&eacute;terie NSERM U927, Facult&eacute; de M&eacute;decine Poitiers France.
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François
Poitiers University School of Medicine Department of Neurosurgery Poitiers France.
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Delmotte
Poitiers University School of Medicine Department of Neurosurgery Poitiers France.
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Rigoard
D000818:Animals; D004281:Docosahexaenoic Acids / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D004789:Enzyme Activation / Q000187:drug effects*; D005260:Female; D007267:Injections; D018482:Muscle, Skeletal / Q000187:drug effects / Q000201:enzymology*; D020033:Protein Isoforms / Q000378:metabolism; D017208:Rats, Wistar; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013119:Spinal Cord Injuries / Q000188:drug therapy / Q000201:enzymology*
D020033:Protein Isoforms; D004281:Docosahexaenoic Acids; D000254:Sodium-Potassium-Exchanging ATPase