Activities of lung NADPH-cytochrome C-reductase and of cytochrome P-450 peroxidase during the protection of rat from hyperoxic injury by polyriboinosinic acid-polyribocytidilic acid.
Rats exposed to normobaric oxygen received a single i.p. injection of 2.5 mg/kg of poly I: poly C at various times (-120 to +36 h) before and after the beginning of oxygen exposure. Hyperoxic lung damage and modifications in cytochrome P-450 system components were evaluated. Our results confirmed the protective effect of poly I: poly C on rats exposed to oxygen, reducing the lung edema and the mortality. This effect was only observed when poly I: poly C was injected 48 or 36 h before the beginning of oxygen exposure. Although oxygen exposure per se decreased the total level of lung cytochrome P-450, poly I: poly C per se induced a deeper decrease to levels similar in air- or oxygen-exposed rats. Poly I: poly C did not modify the NADPH-cytochrome c reductase level nor the cytochrome P-450 peroxidase activity in air-exposed rats. The oxygen exposure induced a decrease of these two enzymes, either in the absence or in the presence of poly I: poly C, except when poly I: poly C was injected 48 or 36 h before the beginning of oxygen exposure, times at which poly I: poly C restored the enzymatic values measured in rats exposed to air. Because the times of injection of poly I: poly C were those at which the protective effect was observed, it suggested that the protective effect of poly I: poly C against oxygen toxicity was associated with a lack of oxygen-induced decrease of both the lung NADPH-cytochrome c reductase level and the lung cytochrome P-450 peroxidase activity.
Coutant-Perronne
V
V
Institut National de la Santé et de la Recherche Médicale, Unité 13, Hôpital Claude Bernard, Paris, France.
Mansour
H
H
Marquetty
C
C
Rouveix
B
B
Pocidalo
J J
JJ
D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D005979:Glutathione Peroxidase / Q000187:drug effects; D005980:Glutathione Reductase / Q000187:drug effects; D008168:Lung / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism*; D010100:Oxygen / Q000009:adverse effects*; D010544:Peroxidases / Q000378:metabolism*; D010996:Pleural Effusion / Q000517:prevention & control; D011070:Poly I-C / Q000627:therapeutic use*; D011654:Pulmonary Edema / Q000517:prevention & control; D051381:Rats; D013482:Superoxide Dismutase / Q000187:drug effects; D013997:Time Factors
D003577:Cytochrome P-450 Enzyme System; D010544:Peroxidases; C066418:cytochrome P-450 peroxygenase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D009251:NADPH-Ferrihemoprotein Reductase; D005980:Glutathione Reductase; D011070:Poly I-C; D010100:Oxygen