Antioxidant treatment does not prevent chronic hypoxia-induced respiratory muscle impairment in developing rats.
Litters of rats were exposed to normobaric normoxia or hypobaric hypoxia (P(B)= 450 mmHg) for 7 days at 3 different time points during early development (postnatal day (P)1, P6 & P11). A separate litter exposed to hypoxia at P11 was treated with the antioxidant Tempol (100 mg/kg) given by oral administration daily starting at P8. At P19, sternohyoid and diaphragm muscles were removed and isolated muscle bundles were mounted isometrically in physiological salt solution at 30 degrees C in vitro. Fatigue was assessed in response to repeated stimulation (40 Hz) every 2 s for 5 min. Fatigue index was measured. Chronic hypoxia decreased sternohyoid, but not diaphragm, muscle endurance. Tempol treatment did not prevent hypoxia-induced muscle plasticity, suggesting that reactive oxygen species are not implicated in hypoxia-induced muscle dysfunction.
Carberry
Jayne
J
UCD School of Medicine and Medical Science, University College Dublin, Dublin 4, Ireland.
Bradford
Aidan
A
O'Halloran
Ken D
KD
D000818:Animals; D003497:Cyclic N-Oxides / Q000494:pharmacology; D003964:Diaphragm / Q000187:drug effects / Q000503:physiopathology; D005260:Female; D016166:Free Radical Scavengers / Q000494:pharmacology*; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D018763:Muscle Fatigue / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D012132:Respiratory Muscles / Q000187:drug effects* / Q000503:physiopathology*; D013113:Spin Labels; D013997:Time Factors
D003497:Cyclic N-Oxides; D016166:Free Radical Scavengers; D013113:Spin Labels; C001803:tempol