We performed this study to determine whether perfused isolated human a
nd rat hepatocytes have different sensitivities to anoxia-reoxygenatio
n injury. Oxygen free radicals were detected by lucigenin-enhanced che
miluminescence. Lipid peroxidation was assessed by measuring malondial
dehyde release. Cell injury was evaluated by measuring lactate dehydro
genase release and trypan blue uptake. During the control period, luci
genin-enhanced chemiluminescence, malondialdehyde and lactate dehydrog
enase release and trypan blue uptake were similar in rat and human hep
atocytes. During 3.5 hr of anoxia, lucigenin-enhanced chemiluminescenc
e decreased to back-ground levels and malondialdehyde release remained
constant in both groups. In contrast, lactate dehydrogenase release i
ncreased eightfold in rat hepatocytes but only threefold in human hepa
tocytes. With reoxygenation after 2.5 hr of anoxia, in rat hepatocytes
lucigenin-enhanced chemiluminescence increased 13-fold within 15 min
and then declined toward control levels. Malondialdehyde release doubl
ed after 1 hr of reoxygenation. The rate of lactate dehydrogenase rele
ase increased to a level almost twice that observed in cells kept cont
inuously anoxic. In contrast, with human hepatocytes lucigenin-enhance
d chemiluminescence increased only fourfold, whereas malondialdehyde a
nd lactate dehydrogenase releases did not differ significantly from th
ose levels measured in cells perfused continuously under anoxic condit
ions. At the end of the experiment, the increase in trypan blue uptake
was significantly greater with rat hepatocytes than with human hepato
cytes. These results demonstrate that (a) during reoxygenation followi
ng 2.5 hr of anoxia, isolated human hepatocytes generate fewer oxygen
free radical, and lipoperoxides than do rat hepatocytes, and (b) human
hepatocytes are more resistant to cell injury during anoxia-reoxygena
tion than are rat hepatocytes.