Purpose. To investigate the pharmacokinetics and preventive effects of liver- targeted catalase (CAT) derivatives on hepatic injury caused by reactive oxygen species.
Methods. The hepatic uptake of In-111-CAT, galactosylated (Gal-), mannosylated (Man-) and succinylated (Suc-) CAT was investigated in isolated perfused rat livers in a single- pass constant infusion mode. Then, pharmacokinetic parameters were obtained by fitting equations derived from a one- organ pharmacokinetic model to the outflow profile. Their effects in preventing hydrogen peroxide- induced injury were determined by lactate dehydrogenase (LDH) release from the perfused liver.
Results. The extraction of CAT derivatives by the liver was dose-dependent, and increased by the chemical modifications described. After being bound to the cell surface, chemically modified CAT derivatives were internalized by the liver faster than CAT. Preperfusion of a CAT derivative significantly reduced LDH release by hydrogen peroxide at least for 30 min, and Man- CAT and Suc- CAT effectively inhibited this release.
Conclusions. Internalized CAT derivatives are also effective in degrading hydrogen peroxide and targeted delivery of CAT to liver nonparenchymal cells by mannosylation or succinylation is a useful method for the prevention of hepatic injury caused by reactive oxygen species.