Sinusoidal endothelial hyperplasia in pathogenesis of perilobular fibrosis in rabbit after experimental ligation of common bile duct.

Development of perilobular hepatic fibrosis in rabbits after experimental ligation of the common bile duct was studied by microscopy. Twelve hours after the ligation, the lobular boundaries assumed prominence by appearance of row(s) of congested sinusoids around the distended perilobular canals of Hering. Seven days later, the lobular laminae limitans around such canals of Hering revealed myxomatous ballooning degeneration forming well defined inter-lobular bands (ILBs). On day 15 post-ligation, the residual sinusoidal endothelial-lining cells in the ILBs manifested hyper chromasia and occasional mitotic activity. It was followed, on days 25 and 35, by proliferation (hyperplasia) of the sinusoidal endothelium cells forming the portal tract like fibrotic tissue in the perilobular bands. These findings, showed the course of interlobular bridging necrosis along the bile preductules at the lobular circumferences and subsequently indigenous origin of the fibrotic tissue in the ILBs from the residual cells in the affected parenchyma independent of the portal tracts.