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document
Hyperbaric oxygen attenuation of lipopolysaccharide-induced acute lung injury involves heme oxygenase-1 . BACKGROUND Hyperbaric oxygen ( HBO ) attenuates lipopolysaccharide ( LPS ) -induced acute lung injury . This beneficial effect of HBO involves inhibition of inducible nitric oxide synthase ( iNOS ) expression and subsequent nitric oxide ( NO ) biosynthesis . We sought to investigate the role of heme oxygenase-1 ( HO-1 ) on this HBO inhibition of iNOS induction and acute lung injury in septic rat lungs . METHODS Before the experiment , 72 rats were randomly allocated to receive HBO or air treatment . With or without HBO pre-treatment , the rats were further divided into the following subgroups ( n = 6 ) : ( i ) LPS injection , ( ii ) normal saline ( N/S ) injection , ( iii ) hemin ( a HO-1 inducer ) plus LPS , ( iv ) hemin alone , ( v ) tin protoporphyrin ( SnPP ; a HO-1 inhibitor ) plus LPS , and ( vi ) SnPP alone . All rats were maintained for 6 h and then sacrificed with a high-dose pentobarbital injection . Lung injuries and relevant enzymes expression were thus assayed . RESULTS Histological analysis , PMNs/alveoli ratio , and wet/dry weight ratio measurements demonstrated that LPS caused significant lung injury and HBO and/or hemin significantly attenuated this LPS-induced lung injury . Increased pulmonary iNOS expression and NO production were associated with lung injury . Induction of HO-1 , by HBO and/or hemin , significantly attenuated this LPS-induced iNOS expression and acute lung injury . SnPP , on the contrary , offset the effects of HBO and worsened the LPS-induced lung injury . CONCLUSIONS HBO may act through inhibiting pulmonary iNOS expression to attenuate LPS-induced acute lung injury in septic rats . Furthermore , this HBO attenuation of iNOS expression involves HO-1 induction .
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Intervention_Pharmacological
Hyperbaric oxygen
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Intervention_Pharmacological
Hyperbaric oxygen ( HBO )
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Intervention_Control
HBO or air treatment
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Intervention_Pharmacological
HBO
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Intervention_Pharmacological
LPS injection
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Intervention_Pharmacological
normal saline ( N/S ) injection
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Intervention_Pharmacological
hemin ( a HO-1 inducer ) plus LPS
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Intervention_Pharmacological
hemin alone
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Intervention_Pharmacological
tin protoporphyrin ( SnPP ; a HO-1 inhibitor )
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Intervention_Pharmacological
LPS
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Intervention_Pharmacological
SnPP alone
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Intervention_Pharmacological
high-dose pentobarbital injection .
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Intervention_Pharmacological
HBO
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Intervention_Pharmacological
HBO
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Intervention_Pharmacological
HBO
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Outcome_Physical
Histological analysis , PMNs/alveoli ratio , and wet/dry weight ratio measurements
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Outcome_Physical
iNOS expression and NO production
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Participant_Condition
lipopolysaccharide-induced acute lung injury
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Participant_Condition
acute lung injury
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Participant_Condition
rat
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Participant_Sample-size
72 rats
23555
Participant_Condition
rats
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Participant_Condition
rats
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Participant_Condition
septic rats