HYALURONAN ACCUMULATES AROUND PORTAL VESSELS IN LIVER AFTER ENDOTOXINTREATMENT OF RATS

Livers of normal rats and rats treated with lipopolysaccharide from Es cherichia coli were isolated in situ and tested for capability to extr act [H-3]-hyaluronan, In control livers, excess unlabeled hyaluronan i nhibited extraction of [H-3]-hyaluronan both at 4 degrees C and 37 deg rees C, Furthermore, part of the [H-3]-hyaluronan extracted at 4 degre es C could be released by subsequent perfusion with excess of unlabele d hyaluronan. This behaviour is in accordance with the well-characteri zed receptor-mediated uptake of hyaluronan in sinusoidal endothelial c ells, However, in lipopolysaccharide-treated animals, the uptake of [H -3]-hyaluronan was not inhibited by unlabelled polysaccharide, nor cou ld [H-3]-hyaluronan bound at 4 degrees C be released from its binding sites, Both types of livers were perfused with 10 mu g/ml of hyalurona n and recovered for histology. An accumulation of hyaluronan in areas around portal veins was found in endotoxin treated rats, while only tr aces of hyaluronan could be visualized in the vessels of normal livers , The location of hyaluronan coincided with cell infiltrates, Thus, th ere is a different mechanism for liver clearance of hyaluronan in the endotoxic animal.