Liver cold storage leads to oxygen free radical production and reperfu
sion injury. Antioxidants are effective in suppressing reperfusion inj
ury in rat livers when used in the reperfusion medium. However, in cli
nical liver transplantation their effectiveness is not clear, which ma
y be due to the way they are used (in the recipient). In this study we
compare the effectiveness of antioxidants when used in the reperfusio
n medium versus the cold storage solution in isolated hepatocytes and
the isolated perfused liver. Hepatocytes were cold stored in UW soluti
on for 24 h. Oxidative stress, induced by t-butyl hydroperoxide (tBHP)
, was measured in the presence of one of five different antioxidants -
deferoxamine (DFO), dithiothreitol(DTT), trolox, tocopherol, dimethyl
thiourea (DMTU) - in the reperfusion buffer or UW solution. Efficacy w
as judged by reduction in membrane damage (LDH release) during rewarmi
ng. Also, rat livers were cold stored for 48 h in UW solution (+/- ant
ioxidant) and reperfused (+/- antioxidants). Efficacy was judged by th
e effect on enzyme release and bile production. Cold storage of hepato
cytes for 24 h sensitized them to oxidative stress. The concentration
of tBHP required to induce maximal cell death (80 %-90 % LDH release)
was reduced from 1.3 mM (fresh cells) to 0.37 mM (LD-50 values). All a
ntioxidants except DMTU suppressed oxyradical-induced LDH release when
used in the reperfusion medium, but only DFO was effective when used
in the UW solution. In the isolated perfused liver, DFO, DTT, and trol
ox were effective and suppressed enzyme release when added to the repe
rfusion buffer, but none were effective when used in the UW solution.
We conclude that cold storage sensitizes liver cells to oxidative stre
ss. The most effective antioxidant was the iron chealator, DFO, which
was effective in the reperfusion buffer (isolated perfused liver or he
patocytes) but not in the UW solution when tested in the isolated perf
used liver. Suppression of reperfusion injury in liver transplantation
could be obtained by antioxidant therapy. However, it is unclear how
best to deliver the antioxidants to the site of oxyradical generation.