Hyperoxia contributes to
acute lung injury in diseases such as
acute respiratory distress syndrome in adults and
bronchopulmonary dysplasia in premature infants.
Cytochrome P450 (
CYP)1A1 has been shown to modulate hyperoxic
lung injury. The mechanistic role(s) of
CYP1A1 in hyperoxic
lung injury in vivo is not known. In this investigation, we hypothesized that
Cyp1a1(-/-) mice would be more susceptible to hyperoxic
lung injury than wild-type (WT) mice, and that the protective role of
CYP1A1 is in part due to CYP1A1-mediated decrease in the levels of
reactive oxygen species-mediated
lipid hydroperoxides, e.g.,
F2-isoprostanes/isofurans, leading to attenuation of oxidative damage. Eight- to ten-week-old male WT (C57BL/6J) or
Cyp1a1(-/-) mice were exposed to
hyperoxia (>95% O2) or room air for 24-72 h. The
Cyp1a1(-/-) mice were more susceptible to
oxygen-mediated lung damage and
inflammation than WT mice, as evidenced by increased lung
weight/body weight ratio,
lung injury, neutrophil infiltration, and augmented expression of
IL-6.
Hyperoxia for 24-48 h induced CYP1A expression at the
mRNA,
protein, and
enzyme levels in liver and lung of WT mice. Pulmonary
F2-isoprostane and isofuran levels were elevated in WT mice after
hyperoxia for 24 h. On the other hand,
Cyp1a1(-/-) mice showed higher levels after 48-72 h of
hyperoxia exposure compared to WT mice. Our results support the hypothesis that
CYP1A1 protects against hyperoxic
lung injury by decreasing oxidative stress. Future research could lead to the development of novel strategies for prevention and/or treatment of
acute lung injury.