1.
NCX-1000, (3alpha, 5beta, 7beta)-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. 2. Here, we demonstrated that administering mice with 40 micromol kg(-1)
NCX-1000, but not UDCA, improves liver histopathology and reduces mortality caused by 330 micromol 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-gamma,
TNF-alpha, Fas/
Fas ligand and
inducible nitric oxide synthase (iNOS)
mRNA accumulation caused by
APAP. 3. In vitro exposure of primary cultures of mouse hepatocytes to
APAP, 6.6 mm, resulted in apoptosis followed by
necrosis. Loss of cell viability correlates with early mitochondrial membrane potential (Deltapsi(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). 4. Treating primary culture of hepatocytes with 5 microm
cyclosporine and 10 microm
trifluoperazine for eight resulted in significant reduction of apoptosis induced by
APAP suggesting that loss of Deltapsim was mechanistically involved in apoptosis induced by
APAP in vitro. 5.
NCX-1000, but not UDCA, concentration-dependently (ED(50)=16 microm) protected against Deltapsi(m) depolarization and reduced transition from apoptosis to
necrosis caused by 6.6 mm
APAP. 6. Treating primary cultures of hepatocytes with the NO-donor
DETA-NO, 100 microm, reduced apoptosis induced by
APAP and prevented
caspase activation. 7. 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.