Redox balance and cellular inflammation in the diaphragm, limb muscles, and lungs of mechanically ventilated rats.
BACKGROUND
High tidal volume (VT) mechanical ventilation was shown to induce organ injury other than lung injury and systemic inflammation in animal models of ventilator-induced lung injury. The authors aimed to explore whether high VT mechanical ventilation per se induces early oxidative stress and inflammation in the diaphragm, limb muscles, and lungs of healthy rats exposed to ventilator-induced lung injury.


METHODS
Protein carbonylation and nitration, antioxidants (immunoblotting), and inflammation (immunohistochemistry) were evaluated in the diaphragm, gastrocnemius, soleus, tibialis anterior, and lungs of mechanically ventilated healthy rats and in nonventilated control animals (n = 8/group) for 1 h, using two different strategies (moderate VT [VT = 9 ml/kg] and high VT [VT = 35 ml/kg]).


RESULTS
The main findings are summarized as follows: compared with controls, (1) the diaphragms and gastrocnemius of high-VT rats exhibited a decrease in reactive carbonyls, (2) the soleus and tibialis of high- and moderate-VT rodents showed a reduction in reactive carbonyls and malondialdehyde-protein adducts, (3) the lungs of high-VT rats exhibited a significant rise in malondialdehyde-protein adducts, (4) the soleus and tibialis of both high- and moderate-VT rats showed a reduction in protein nitration, (5) the lungs of high- and moderate-VT rats showed a reduction in antioxidant enzyme levels, but not in the muscles, and (6) the diaphragms and gastrocnemius of all groups exhibited very low inflammatory cell counts, whereas the lungs of high-VT rats exhibited a significant increase in inflammatory infiltrates.


CONCLUSIONS
Although oxidative stress and inflammation increased in the lungs of rats exposed to high VT, the diaphragm and limb muscles exhibited a decline in oxidative stress markers and very low levels of cellular inflammation.
Marín-Corral
Judith
J
Institut Municipal d'Investigació Mèdica-Hospital del Mar, Parc de Recerca Biomèdica de Barcelona, Department of Medicine, Medical School, Universitat Autònoma de Barcelona, Barcelona, Spain.
Martínez-Caro
Leticia
L
Lorente
José A
JA
de Paula
Marta
M
Pijuan
Lara
L
Nin
Nicolas
N
Gea
Joaquim
J
Andrés
Esteban
E
Barreiro
Esther
E
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D015415:Biomarkers; D002374:Catalase / Q000378:metabolism; D003964:Diaphragm / Q000473:pathology*; D007150:Immunohistochemistry; D007249:Inflammation / Q000473:pathology*; D008168:Lung / Q000473:pathology*; D008315:Malondialdehyde / Q000378:metabolism; D018656:Muscle Fibers, Fast-Twitch / Q000502:physiology; D018657:Muscle Fibers, Slow-Twitch / Q000502:physiology; D018482:Muscle, Skeletal / Q000473:pathology*; D009566:Nitrates / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D050050:Protein Carbonylation; D051381:Rats; D012121:Respiration, Artificial / Q000009:adverse effects*; D013482:Superoxide Dismutase / Q000378:metabolism; D013990:Tidal Volume / Q000502:physiology; D014443:Tyrosine / Q000378:metabolism; D055397:Ventilator-Induced Lung Injury
D000975:Antioxidants; D015415:Biomarkers; D009566:Nitrates; D014443:Tyrosine; D008315:Malondialdehyde; D002374:Catalase; D013482:Superoxide Dismutase