Fibronectin and type I collagen distribution in primary stage of experimental hepatic fibrosis

The localization of fibronectin (FN) and type I collagen in livers of normal rats and simular animals administered CCl4 was investigated using immunoperoxidase techniques. Continuous observation of the respective specimens in these experiments were done on electron microscope.Neither FN nor type I collagen was found in any hepatocytes and sinusoids of normal rat livers, except in a small amount in the central and portal areas. In CCl4-induced hepatic fibrosis, FN was first distributed from plasma, followed by type I collagen distribution on the relevant FN deposits. These latter matrix proteins were found to exhibit a distribution pattern similar to that of FN.From these results and other reports, primary changes in liver fibrosis due to the administration of CCl4 are assumed to occur as follows:FN is first deposited from plasma together with macrophages and fibroblasts, followed by the secretion of type I collagen in the FN deposits by infiltrated fibroblasts, and/or transported Ito cells.