Effects of bleomycin on 14C‐proline uptake, its incorporation into proteins and hydroxylation in collagenous proteins of hamster lung slices

The uptake of 14C‐proline by lung slices and its incorporation into trichloroacetic‐acid (TCA)‐insoluble proteins and hydroxylation in collagenous proteins were studied. They were found to be linearly increased with the incubation time for as long as 8 h. The effects of different concentrations of bleomycin on these parameters were subsequently investigated. Bleomycin at 10−3M significantly reduced the uptake of 14C‐proline to 75% of the control value. The incorporation of 14C‐proline into TCA‐insoluble proteins was reduced to 84%, 78% and 75% of the control at 2.5 × 10−4M, 5 × 10−4M and 10−3M concentrations of bleomycin, respectively. Bleomycin failed to alter the proline pool size of the lung slices at any of these concentrations. In addition, bleomycin also inhibited the hydroxylation of 14C‐proline into collagen to 72% and 69% of the control at 5 × 10−4M and 10−3M, respectively. These findings show that bleomycin‐induced increases in collagen synthesis in vivo is probably secondary to inflammatory reactions of the lung and bleomycin per se has little effect on increased collagen synthesis responsible for lung fibrosis.

[1]  Y. Lin,et al.  Active transport of foreign amino acids by rat lung slices. , 1981, Biochemical pharmacology.

[2]  S. Kerwar,et al.  The in vivo inhibition of collagen synthesis and the reduction of prolyl hydroxylase activity by 3,4-dehydroproline. , 1976, Archives of biochemistry and biophysics.

[3]  S. Kerwar,et al.  Studies on the effect of 3,4-dehydroproline on collagen metabolism in carbon tetrachloride-induced hepatic fibrosis. , 1977, Archives of biochemistry and biophysics.

[4]  S. Crooke,et al.  Cisplatin : current status and new developments , 1980 .

[5]  J. Lindsley,et al.  A photometric method for the determination of proline. , 1955, The Journal of biological chemistry.

[6]  S. Giri,et al.  Effects of intratracheal administration of bleomycin on GSH-shuttle enzymes, catalase, lipid peroxidation, and collagen content in the lungs of hamsters. , 1983, Toxicology and applied pharmacology.

[7]  R. McAnulty,et al.  Protein metabolism during bleomycin-induced pulmonary fibrosis in rabbits. In vivo evidence for collagen accumulation because of increased synthesis and decreased degradation of the newly synthesized collagen. , 1983, The American review of respiratory disease.

[8]  M. Montgomery,et al.  Biochemical and morphological assessments of bleomycin pulmonary toxicity in rats. , 1980, Toxicology and applied pharmacology.

[9]  C. Cross,et al.  Bleomycin-induced pulmonary fibrosis: correlation of biochemical, physiological, and histological changes. , 1981, Toxicology and applied pharmacology.

[10]  O. H. Lowry,et al.  Protein measurement with the Folin phenol reagent. , 1951, The Journal of biological chemistry.

[11]  T. Dipetrillo,et al.  Collagen lysyl oxidase activity in the lung increases during bleomycin-induced lung fibrosis. , 1981, The Journal of pharmacology and experimental therapeutics.

[12]  R. Newman,et al.  Bleomycin-induced pulmonary fibrosis in the rat. Prevention with an inhibitor of collagen synthesis. , 1980, The Journal of laboratory and clinical medicine.

[13]  M. Luna,et al.  Interstitial pneumonitis associated with bleomycin therapy. , 1972, American journal of clinical pathology.

[14]  D. Chandler,et al.  Increases in lung prolyl hydroxylase and superoxide dismutase activities during bleomycin-induced lung fibrosis in hamsters. , 1983, Experimental and molecular pathology.

[15]  I. Adamson,et al.  Bleomycin-induced injury and metaplasia of alveolar type 2 cells. Relationship of cellular responses to drug presence in the lung. , 1979, The American journal of pathology.

[16]  M. Chvapil.  Pharmacology of fibrosis: definitions, limits and perspectives. , 1975, Life sciences.

[17]  D. Prockop,et al.  Modified procedure for the assay of H-3-or C-14-labeled hydroxyproline. , 1966, Analytical biochemistry.

[18]  U. Fricke,et al.  Tritosol: a new scintillation cocktail based on Triton X-100. , 1975, Analytical biochemistry.

[19]  Lewis L. Smith,et al.  Evidence for energy-dependent accumulation of paraquat into rat lung , 1974, Nature.

[20]  I. Raisfeld.  Pulmonary toxicity of bleomycin analogs. , 1980, Toxicology and applied pharmacology.

[21]  D. Hyde,et al.  Morphometric estimates of infiltrative cellular changes during the development of bleomycin-induced pulmonary fibrosis in hamsters. , 1983, The American journal of pathology.

[22]  M. Hollinger,et al.  Evaluation of antifibrotic drugs in bleomycin-induced pulmonary fibrosis in hamsters. , 1980, The Journal of pharmacology and experimental therapeutics.

[23]  M. Hollinger,et al.  Effects in vitro and in vivo of thioureas on acetylcholine esterase activity of rat tissues. , 1977, Biochemical pharmacology.

[24]  P. Ward,et al.  Bleomycin-induced pulmonary fibrosis in the rat: inhibition by indomethacin. , 1979, The American journal of pathology.

[25]  L. Schwartz,et al.  Biochemical and structural alterations of hamster lungs in response to intratracheal administration of bleomycin. , 1980, Experimental and molecular pathology.

[26]  J. Uitto,et al.  Protocollagen proline hydroxylase activity in experimental pulmonary fibrosis of rats. , 1970, The Journal of laboratory and clinical medicine.