Published in:
01-07-2004 | Experimental
Role of PARP on iNOS pathway during endotoxin-induced acute lung injury
Published in: Intensive Care Medicine | Issue 7/2004
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Objective
Excessive nitric oxide (NO) and especially peroxynitrite may cause pulmonary tissue damage, e.g., through lipid peroxidation and/or exhaustion of cellular energy depletion induced by activation of poly (ADP-ribose) polymerase (PARP). Furthermore, PARP seems to aggravate tissue destruction by regulating the expression of respective genes.
Design
Prospective animal study.
Setting
University research laboratory.
Intervention
We investigated the effect of competitive PARP inhibition by 3-aminobenzamide (3-AB) on the pulmonary iNOS pathway after infusion of lipopolysaccharide (LPS).
Measurements and results
The pretreatment of rabbits with 3-AB attenuated the LPS-induced iNOS mRNA and protein expression analyzed by RT-PCR and Western blot, and plasma nitrite concentrations quantified by Griess reaction (71±6%, 93±6% vs baseline). Electromobility shift assay showed an enhanced NF-κB and attenuated AP-1 activation after 3-AB vs LPS alone. Lipid peroxidation determined as levels of thiobarbituric acid reactive substances in plasma and lung tissue was reduced by 50% in the LPS+3-AB in comparison to LPS alone. Simultaneously, 3-AB was able to inhibit correspondingly the LPS-induced extravasation of gold-labeled albumin and increase of alveolo-arterial oxygen difference.
Conclusion
PARP regulates the pulmonary NO pathway during endotoxemia via AP-1 and not NF-κB. Thus, pharmacological inhibition of PARP might be an effective intervention to prevent endotoxin-induced lung injury, interrupting the vicious circle of NO production and PARP activation.