[Effects of hyperoxia on Wistar rat lungs].
OBJECTIVE
To study the effects of short-term exposure to high oxygen concentrations (hyperoxia) on Wistar rat lungs.


METHODS
Animals were divided into three groups exposed to hyperoxia for 10', 30' and 90' (O10', O30', O90', respectively), together with a control group (exposed to room air). The animals were sacrificed 24 h after exposure. Bronchoalveolar lavage was performed, and the lungs were removed for histological and stereological analysis.


RESULTS
In the O10', O30', and O90' groups, respectively and in comparison with the controls, we observed an increase in the numbers of macrophages (2169.9 +/- 118.0, 1560.5 +/- 107.0, and 1467.6 +/- 39.0 vs. 781.3 +/- 78.3) and neutrophils (396.3 +/- 35.4, 338.4 +/- 17.3, and 388.7 +/- 11.7 vs. 61.6 +/- 4.2), concomitant with an increase in oxidative damage (143.0 +/- 7.8%, 180.4 +/- 5.6%, and 235.0 +/- 13.7 vs. 100.6 +/- 1.7%). The histological and stereological analyses revealed normal alveoli and alveolar septa in the controls (83.51 +/- 1.20% and 15 +/- 1.21%), in the O10' group (81.32 +/- 0.51% and 16.64 +/- 0.70%), and in the O30' group (78.75 +/- 0.54% and 17.73 +/- 0.26%). However, in the O90' group, inflammatory cell infiltration was observed in the alveoli and alveolar septa. Red blood cells extravasated from capillaries to the alveoli (59.06 +/- 1.22%), with evidence of congestion, hemorrhage, and septal edema (35.15 +/- 0.69%).


CONCLUSIONS
Hyperoxia for 90' caused injury of the lung parenchyma, resulting in oxidative damage and inflammatory cell infiltration.
Valença
Samuel Dos Santos
Sdos S
Departamento de Histologia e Embriologia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brasil. samuelv@hotmail.com
Kloss
Milena Leonarde
ML
Bezerra
Frank Silva
FS
Lanzetti
Manuella
M
Silva
Fabiano Leichsenring
FL
Porto
Luís Cristóvão
LC
D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D004195:Disease Models, Animal; D004487:Edema / Q000473:pathology; D006470:Hemorrhage / Q000473:pathology; D018496:Hyperoxia / Q000139:chemically induced / Q000473:pathology*; D008168:Lung / Q000187:drug effects / Q000473:pathology*; D016676:Macrophages, Alveolar / Q000473:pathology; D008297:Male; D009504:Neutrophils / Q000473:pathology; D018384:Oxidative Stress / Q000187:drug effects*; D010100:Oxygen / Q000008:administration & dosage / Q000009:adverse effects*; D011650:Pulmonary Alveoli / Q000187:drug effects / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D010100:Oxygen