Regulation of extracellular matrix production in the stellate cells - An analysis in the liver of LEC rats

This report provides the first detailed description of hepatic stellate cel ls in Long-Evans cinnamon-like colored (LEC) rats. To investigate the role of hepatic stellate cells in induction or suppressi on of hepatic fibrosis, we morphologically examined the liver of LEC rats. The LEC rat showed excessive accumulation of copper in hepatic parenchymal cells at 5 weeks and submassive necrosis at 9 weeks of age. The liver of LE C rats 1.5 years of age showed cholangiofibrosis and subcellular injury of hepatic parenchymal cells. However, no diffuse hepatic fibrosis was observe d in the liver of the rats at this age, namely, 1.5 years; and hepatic stel late cells around the region of cholangiofibrosis were negative for alpha-s mooth muscle actin (ASMA). Throughout the experimental period, the stellate cells retained many vitamin A-lipid droplets, and no excessive accumulatio n of collagen fibers was observed around these cells. The hepatic stellate cells did not participate in accumulating collagen fibers around themselves when the cells contained lipid droplets, although the hepatic lesions were in progress. Morphometric analysis showed that stellate cells in the liver of LEC rats contained a higher amount of lipid droplets compared to the co ntrol rat. These results are consistent with our hypothesis that there is a n antagonistic relationship between the storage of vitamin A and the produc tion of collagen in stellate cells.