Morphological and Biochemical Assessment of Papain-Induced Emphysema

Our plain-English summary of Morphological and Biochemical Assessment of Papain-Induced Emphysema, by K.H. Kilburn, A.R. Dowell, P.C. Pratt (1971).

The study

• Authors: K.H. Kilburn, A.R. Dowell, P.C. Pratt
• Published: Archives of Internal Medicine, Volume 127. May 1971
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This was an animal experiment, and it does not involve asbestos. The authors injected Syrian hamsters once into the windpipe with 1 mg of purified papain, a protein-digesting enzyme, to create a model of emphysema. The article mentions 64 hamsters and 16 control animals, but the scan is too damaged to show whether the controls were among the 64. The comparison lung slices came from saline-injected animals. Animals were killed at intervals up to 64 days. Twelve hours after papain, the lungs were heavier and hemorrhagic, and electron microscopy showed collagen fibrils in the air-sac walls losing definition. By 4 days the walls between air sacs had broken down (departitioning), and the lesions looked unchanged from 8 to 64 days. Treated hamsters grew at the same rate as controls. Lecithin production in lung slices did not differ from controls. Protein production was greater in slices from three treated animals than from three control animals. Total lung collagen and elastin were unchanged. The authors concluded that a single dose produced departitioning resembling centrilobular emphysema within four days. They noted that amino acid pool size was not corrected for, that cell numbers were not measured, and that the collagen finding was tentative.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Animal experiment: a single intratracheal dose of papain in hamsters, compared with control animals. Lungs were examined by light and electron microscopy, and lung slices were used for biochemical tests in the laboratory.
• Who was studied: Syrian hamsters of both sexes, weighing 50 to 120 g. The article mentions sixty-four hamsters and 16 control animals. Damaged text hides whether the controls were counted within the 64. Animals were killed at intervals up to 64 days after injection. The ages are unreadable in the scanned text.
• Exposure: One intratracheal injection of 1 mg of purified papain (an enzyme) in saline solution. Controls were saline-injected. No asbestos or other fibers were studied.
• Main results:
  • In papain-treated hamsters at 12 hours, the lungs had increased wet weight and were hemorrhagic.
  • Electron microscopy of papain-treated lungs at 12 hours showed loss of definition of collagen fibrils in the alveolar walls.
  • In papain-treated lungs, alveolar departitioning was recognizable by 4 days and appeared unchanged from 8 days to 64 days.
  • Lecithin synthesis in lung slices from papain-treated hamsters was not different from that in slices from control (saline-injected) hamsters.
  • Incorporation of four amino acids into protein (protein synthesis) was greater at 30 and 60 minutes in lung slices from three papain-treated animals than in slices from three saline-treated animals.
  • Lung collagen and elastin contents in papain-treated hamsters were unchanged from control at 1, 4, 8, and 12 or 16 days after papain.
• The authors' conclusion: The authors concluded that alveolar departitioning resembling centrilobular emphysema was produced four days after a single intratracheal dose of papain in the hamster, and that the model should be useful for further study of its morphologic and metabolic mechanisms.
• Limitations the authors state:
  • No correction was made for amino acid pool size in the lung slices.
  • Cell numbers were not measured.
  • Conditions were not optimal for choline incorporation (the lecithin measurement) in slices incubated in tromethamine buffer.
  • The authors said the collagen finding should be regarded as tentative until confirmed by a more specific method.

Topics

Medical terms in this study, explained in our Lexicon: Emphysema, Collagen, Fibril.

Browse return to medical research.