Low-intensity swimming training partially inhibits lipopolysaccharide-induced acute lung injury.
BACKGROUND
Aerobic exercise decreases pulmonary inflammation and remodeling in experimental models of allergic asthma. However, the effects of aerobic exercise on pulmonary inflammation of nonallergic origin, such as in experimental models of acute lung injury induced by lipopolysaccharide (LPS), have not been evaluated.


OBJECTIVE
The present study evaluated the effects of aerobic exercise in a model of LPS-induced acute lung injury.


METHODS
BALB/c mice were divided into four groups: Control, Aerobic Exercise, LPS, and Aerobic Exercise + LPS. Swimming tests were conducted at baseline and at 3 and 6 wk. Low-intensity swimming training was performed for 6 wk, four times per week, 60 min per session. Intranasal LPS (1 mg x kg(-1) (60 microg per mouse)) was instilled 24 h after the last swimming physical test in the LPS and Aerobic Exercise + LPS mice, and the animals were studied 24 h after LPS instillation. Exhaled nitric oxide, respiratory mechanics, total and differential cell counts in bronchoalveolar lavage, and lung parenchymal inflammation and remodeling were evaluated.


RESULTS
LPS instillation resulted in increased levels of exhaled nitric oxide (P < 0.001), higher numbers of neutrophils in the bronchoalveolar lavage (P < 0.001) and in the lung parenchyma (P < 0.001), and decreased lung tissue resistance (P < 0.05) and volume proportion of elastic fibers (P < 0.01) compared with the Control group. Swim training in LPS-instilled animals resulted in significantly lower exhaled nitric oxide levels (P < 0.001) and fewer neutrophils in the bronchoalveolar lavage (P < 0.001) and the lung parenchyma (P < 0.01) compared with the LPS group.


CONCLUSIONS
These results suggest that low-intensity swimming training inhibits lung neutrophilic inflammation, but not remodeling and impaired lung mechanics, in a model of LPS-induced acute lung injury.
Ramos
Daniel Souza
DS
Laboratory of Physiology and Pharmacodynamics, Institute of Research and Development, University of Vale do Paraíba, Săo Paulo, Brazil.
Olivo
Clarice Rosa
CR
Quirino Santos Lopes
Fernanda Degobbi Tenório
FD
Toledo
Alessandra Choqueta
AC
Martins
Milton Arruda
MA
Lazo Osório
Rodrigo Alexis
RA
Dolhnikoff
Marisa
M
Ribeiro
Wellington
W
Vieira
Rodolfo de Paula
RP
D000704:Analysis of Variance; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid; D018836:Inflammation Mediators / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009504:Neutrophils / Q000187:drug effects; D009569:Nitric Oxide / Q000378:metabolism; D010805:Physical Conditioning, Animal; D012128:Respiratory Distress Syndrome / Q000139:chemically induced* / Q000517:prevention & control*; D015656:Respiratory Mechanics; D013550:Swimming / Q000502:physiology*
D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D009569:Nitric Oxide