Extracellular matrix in hepatic granulomas of mice infected with Schistosoma mansoni. Qualitative and quantitative analysis.

To investigate the role of extracellular matrix molecules in the granulomatous inflammation, cercariae of Schistosoma mansoni were injected subcutaneously into BALB/c mice. Well-organized granulomas consisting mainly of stimulated macrophages and epithelioid cells developed in the liver at 11 weeks after infection, thereafter showing a tendency to heal. Fibronectin and heparan sulfate proteoglycan deposition appeared around parasite eggs, then increased distinctly at 11 weeks after infection, and subsequently diminished. Quantities of glycosaminoglycans and hydroxyproline in the egg lesion increased significantly at 11 weeks after infection. Thereafter, the amounts of glycosaminoglycans decreased, whereas hydroxyproline content did not. The data suggest that fibronectin and other macromolecules interact to form granuloma extracellular matrix, and that these extracellular events participate in the development of granulomatous inflammation and subsequent fibrosis induced by schistosome eggs.