Liver delivery of NO by NCX‐1000 protects against acute liver failure and mitochondrial dysfunction induced by APAP in mice THIS ARTICLE HAS BEEN RETRACTED

NCX‐1000, (3 α , 5 β , 7 β )‐3,7‐dihydroxycholan‐24oic acid[2‐methoxy‐4‐[3‐[4‐(nitroxy)butoxy]‐3‐oxo‐1‐propenyl]phenyl ester, is a nitric oxide (NO)‐derivative of ursodeoxyxholic acid (UDCA) that selectively release NO in the liver. Here, we demonstrated that administering mice with 40 μ mol kg −1 NCX‐1000, but not UDCA, improves liver histopathology and reduces mortality caused by 330 μ mol kg −1 APAP from 60 to 25% ( P <0.01). Administration of NCX‐1000, in a therapeutic manner, that is, 2 h after acetaminophen (APAP) intoxication reduced mortality, improved liver histopathology and prevented liver IFN‐ γ , TNF‐ α , Fas/Fas ligand and inducible nitric oxide synthase (iNOS) mRNA accumulation caused by APAP.In vitro exposure of primary cultures of mouse hepatocytes to APAP, 6.6 m M , resulted in apoptosis followed by necrosis. Loss of cell viability correlates with early mitochondrial membrane potential (Δ ψ m ) hyperpolarization followed by depolarization and cytochrome c translocation from mitochondria to cytosol. APAP‐induced apoptosis associated with procaspase‐3 and ‐9 cleavage, appearance of truncated Bid and activation of poly(ADP‐ribose) polymerase (PARP). Treating primary culture of hepatocytes with 5 μ M cyclosporine and 10 μ M trifluoperazine for eight resulted in significant reduction of apoptosis induced by APAP suggesting that loss of Δ ψ m was mechanistically involved in apoptosis induced by APAP in vitro . NCX‐1000, but not UDCA, concentration‐dependently (ED 50 =16 μ M ) protected against Δ ψ m depolarization and reduced transition from apoptosis to necrosis caused by 6.6 m M APAP. Treating primary cultures of hepatocytes with the NO‐donor DETA‐NO, 100 μ M , reduced apoptosis induced by APAP and prevented caspase activation. In conclusion, NCX‐1000 is effective in protecting against APAP‐induced hepatotoxicity when administered in a therapeutic manner. This protection may involve the inhibition of apoptosis and the maintenance of mitochondrial integrity.British Journal of Pharmacology (2004) 143 , 33–42. doi: 10.1038/sj.bjp.0705780