Background/aims: Mast cells are thought to be related to fibrogenesis, but recent studies have shown that fibrosis of the liver can be induced even in mast cell-deficient rats. To clarify the significance of mast cell accumulation in cholestatic liver diseases, the relations between such accumulation, bile ductule proliferation and apoptosis of biliary epithelial cells were examined in the rats during cholestasis and its resolution.
Methods: Cholestasis and its resolution were induced in rats by common bile duct ligation and spontaneous recanalization, respectively. The extent of bile ductule proliferation and the numbers of mast cells and apoptotic biliary epithelial cells were estimated quantitatively in liver sections.
Results: Recanalization of the ligated common bile duct led to an abrupt and transient increase in the number of mast cells, although the number of proliferated bile ductules decreased rapidly. The number of apoptotic biliary epithelial cells of the proliferated bile ductules increased rapidly and transiently, and the change paralleled that of the mast cells.
Conclusions: Mast cells accumulating in the portal triads during cholestasis and its resolution may relate to the reduction of proliferated bile ductules, i.e., in hepatic remodeling, through the induction of apoptosis of biliary epithelial cells.