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Early Decrease in Rotenone‐Sensitive Coenzyme Q1 Reduction in Intact Lungs From Rats Exposed to Hyperoxia
Author(s) -
Audi Said,
Bongard Robert,
Roerig David,
Eisenhauer Jessica,
Merker Marilyn
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1083-a
Subject(s) - hyperoxia , rotenone , lung , pulmonary artery , chemistry , perfusion , endocrinology , medicine , andrology , anesthesia , mitochondrion , biochemistry
The objective of this study was to evaluate biochemical changes in lung tissue that may precede the gross lung structural and hemodynamic changes associated with exposure to hyperoxia (85% O 2 ) for > 3 days. We measured the rate of appearance of the hydroquinone form (CoQ 1 H 2 ) of coenzyme Q 1 (CoQ 1 ) in the venous effluent during CoQ 1 infusion at different concentrations into the pulmonary artery of isolated perfused lungs from adult rats exposed to either room air (normoxic) or 85% O 2 (hyperoxic) for 48 hrs. Kinetic analysis of the data revealed that hyperoxia decreased the maximum rate of CoQ 1 H 2 appearance in the venous effluent (V max ) from 9.35 ± 0.42 (SE) μmol/min/g dry lung wt for normoxic lungs (n = 6) to 7.62 ± 0.23 for hyperoxic lungs (n = 6), with no effect on lung wet weight, wet‐to‐dry weight ratio or pulmonary artery pressure. Lung perfusion with rotenone (20 μM), an inhibitor of mitochondrial complex I, decreased V max values to 5.77 ± 0.63 for normoxic lungs (n = 4) and 5.85 ± 0.17 for hyperoxic lungs (n = 4). These V max values for rotenone‐insensitive CoQ 1 reduction in normoxic and hyperoxic lungs are not significantly different. These results suggest that rat exposure to hyperoxia for 48 hrs decreases rotenone sensitive lung CoQ 1 reductase activity by ~ 50% and that this decrease is a potential early index of hyperoxia‐induced pulmonary oxidative stress. Support: HL‐24349, HL‐65537, and Dept. of Veterans’ Affairs.