AGE DEPENDENT DIFFERECES IN SUPEROXIDE PRODUCTION BY STIMULATED RAT KUPFFER CELLS IN THE PRESENCE OF UNINHIBITED TRYPSIN

Abstract

The role of oxidants in hepatocyte injury is currently being considered. Infants and children with α1AT deficiency are more prone to hepatocyte injury than adults. We have begun in vitro investigations of the cells closest to hepatocytes (Kupffer cells) in regards to their extracellular superoxide production in the presence or absence of an uninhibited protease. Kupffer cells were isolated from rat liver by perfusion and incubation with pronase, centrifugal elutriation, and culturing for 24 hours. Over 95% of the cells studied were viable throughout the experiments as determined by trypan blue exclusion and were identified as Kupffer cells by combined giemsa and peroxidase staining. Superoxide was determined in HBSS by the reduction of cytochrome C in the presence or absence of superoxide dismutase (SOD). Resting cells produced essentially no SO.Trypsin (50 ug incubated for 20 minutes before start of experiment). PMA (Phorbol myristate acetate .002 mg). Opsonized Zymosan (1.25 mg). These results suggest that Kupffer cells from younger rats may respond differently to zymosan and PMA in the production of oxidants in the presence of a protease.