Histopathological study of collagen components in pulmonary fibrosis

Research Project

Project/Area Number	60570140
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	Human pathology
Research Institution	TOKYO MEDICAL AND DENTAL UNIVERSITY
Principal Investigator	MATSUBARA. Osamu TOKYO MEDICAL AND DENTAL UNIVERSITY, Assistant Professor, 医学部, 助教授 (40107248)
Project Period (FY)	1985 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥1,800,000 (Direct Cost: ¥1,800,000) Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1985: ¥1,300,000 (Direct Cost: ¥1,300,000)
Keywords	Pulmonary fibrosis / collagen / Fibrosis / パラコート
Research Abstract	For analysis of collagen components in pulmonary fibrosis, solubilization of collagen components in lungs was attempted. For rat lungs papain was effective with complete solubilization, but for human lungs solubilization by pepsin left 27% of the total dry weight of the initial materials, while papain was better in solubilization of fibrotic lungs (residues about 13%). Collagen solubilized was analysed by SDS-urea polyacrylamide gel electrophoresis. The relative amout of type <III> to type <I> collagen in rat lungs increased a few days after injection of paraquat, then decreased to the normal level. The relative ratios of alphaI( <III> ) to alphaI( <I> ) and of alphaI( <I> ) to alphaI( <V> ) of solubilized collagen from human lungs were enhanced in the human fibrotic lungs. The amount of collagen solubilized and recovered was less in normal lungs, one-fourth of that in fibrosis. The resultscan be interpreted in three ways: 1) Normal lungs contain a higher amount of proteases-labile collagens which may be digested away during the protease treatment; 2) Normal lungs contain a higher potential activity for collagen degradation which may be activated during the protease treatment; 3) Normal lung tissues contain a higher amount of protease-insoluble collagen. Changes in the architectures of normal and fibrotic lungs were examined immunohistologically with specific antibodies against types <I> , <III> and <IV> collagens. The relation between biochemical analysis and immunohistological observations must be further examined.