抄録
Serum N-acetyl-β-glucosaminidase (GL) activity, monoamine oxidase (MAO) activity, and hydroxyproline concentration were determined during the progress of experimental pulmonary fibrosis in rabbits monthly for 4 months. The rabbits received intravenous injections of N-methyl-N-nitrosourethane (MNU) (1mg/Kg of body weight, 6 times a month for 5 to 9 months). GL and MAO activities, and hydroxyproline concentration of the pulmonary tissue of the MNU-treated rabbits were also determined.
Results obtained were as follows.
1) The values of GL activity in serum from rabbits before treatment ranged from 2.8 to 7.5 units per dl with a mean value of 5.3 units. The serum GL activity rose remarkably and ranged from 7.8 to 20.4 units with a mean value of 14.2 units after 6 injections of MNU, when the animals treated with MNU were considered to be at the stage of the interstitial pneumonitis. Significantly high GL activity continued for the 4 months of the experimental period.
2) Serum MAO activity in the MNU-treated rabbits increased as the pulmonary fibrosis advanced.
3) Serum hydroxyproline concentration in the MNU-treated rabbits decreased gradually with the development of experimental pulmonary fibrosis.
4) A fairly good correlation was seen between the severity of the histopathological pulmonary fibrosis and hydroxyproline concentration of the lung tissue.
5) There was atypical proliferation of the bronchioloalveolar epithelium associated with foci of severe pulmonary fibrosis in rabbits treated with MNU fro 9 months.
6) GL and MAO activity of lung tissue homogenate of the rabbits treated with MNU were also determined. The values of GL activity in fibrotic lung tissue ranged from 14.1 to 25.1 units per mg of lung tissue. The values of MAO activity ranged from 27.0 to 79.4 units per 5mg of lung tissue.
