Abstract
Intrapulmonary deposition of the proteolytic enzyme papain produces a lesion resembling emphysema in experimental animals. The natural history of this lesion has not been well defined. The present study was performed to evaluate changes in lung structure and function with aging in normal rats and rats exposed to an aerosol of papain at 2 mo of age. Groups of control and papain-exposed animals were studied at 4, 8, and 18 mo of age. The parameters of lung function studied were specific airways' conductance (Gaw/TGV), diffusing capacity per unit of alveolar volume (DLco/VA), diffusing capacity (DLco), and functional residual capacity (FRC). Morphometric parameters were the postfixation lung volume (VL) and mean chord length (LM); internal surface area (ISA) and ISA extrapolated to both the mean VL of the corresponding papain group and a VL of 10 ml (ISA10) were calculated.
At 4 mo of age LM and FRC were significantly increased and ISA, DLco/VA, and DLco were significantly reduced in the papain group. At 8 mo of age LM was significantly increased and ISA was significantly decreased in the papain group: physiologic studies were not performed in this group. At 18 mo of age LM was significantly increased and DLco/VA, DLco, and ISA were significantly decreased. Neither progression nor healing of the lesion was observed despite similar lung growth in both groups.
This study demonstrates that a single proteolytic lung injury produces a fixed deficit of lung parenchyma. Progressive lung destruction may require repeated or continuous lung injury.
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- Blenkinsopp W. K. Bronchiolar damage and emphysema: a study in rats. J Pathol Bacteriol. 1968 Apr;95(2):495–502. doi: 10.1002/path.1700950222. [DOI] [PubMed] [Google Scholar]
- Burri P. H., Weibel E. R. Influence of environmental P-O2 on the growth of the pulmonary gas exchange apparatus. Chest. 1971 May;59(Suppl):25S+–25S+. doi: 10.1016/s0012-3692(15)31573-7. [DOI] [PubMed] [Google Scholar]
- CAMPBELL H., TOMKEIEFF S. I. Calculation of the internal surface of a lung. Nature. 1952 Jul 19;170(4316):116–117. [PubMed] [Google Scholar]
- Caldwell E. J. Physiologic and anatomic effects of papain on the rabbit lung. J Appl Physiol. 1971 Sep;31(3):458–465. doi: 10.1152/jappl.1971.31.3.458. [DOI] [PubMed] [Google Scholar]
- GROSS P., PFITZER E. A., TOLKER E., BABYAK M. A., KASCHAK M. EXPERIMENTAL EMPHYSEMA: ITS PRODUCTION WITH PAPAIN IN NORMAL AND SILICOTIC RATS. Arch Environ Health. 1965 Jul;11:50–58. doi: 10.1080/00039896.1965.10664169. [DOI] [PubMed] [Google Scholar]
- Giles R. E., Finkel M. P., Leeds R. The production of an emphysema-like condition in rats by the administration of papain aerosol. Proc Soc Exp Biol Med. 1970 May;134(1):157–162. doi: 10.3181/00379727-134-34750. [DOI] [PubMed] [Google Scholar]
- Goldring I. P., Greenburg L., Ratner I. M. On the production of emphysema in Syrian hamsters by aerosol inhalation of papain. Arch Environ Health. 1968 Jan;16(1):59–60. doi: 10.1080/00039896.1968.10665015. [DOI] [PubMed] [Google Scholar]
- Johanson W. G., Jr, Pierce A. K. A noninvasive technique for measurement of airway conductance in small animals. J Appl Physiol. 1971 Jan;30(1):146–150. doi: 10.1152/jappl.1971.30.1.146. [DOI] [PubMed] [Google Scholar]
- Johanson W. G., Jr, Pierce A. K. Effects of elastase, collagenase, and papain on structure and function of rat lungs in vitro. J Clin Invest. 1972 Feb;51(2):288–293. doi: 10.1172/JCI106813. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Johanson W. G., Jr, Pierce A. K., Reynolds R. C. The evolution of papain emphysema in the rat. J Lab Clin Med. 1971 Oct;78(4):599–607. [PubMed] [Google Scholar]
- Macklem P. T. Obstruction in small airways--a challenge to medicine. Am J Med. 1972 Jun;52(6):721–724. doi: 10.1016/0002-9343(72)90077-0. [DOI] [PubMed] [Google Scholar]
- Palecek F., Palecekova M., Aviado D. M. Emphysema in immature rats. Condition produced by tracheal constriction and papain. Arch Environ Health. 1967 Sep;15(3):332–342. doi: 10.1080/00039896.1967.10664929. [DOI] [PubMed] [Google Scholar]
- Park S. S., Goldring I. P., Shim C. S., Williams M. H., Jr Mechanical properties of the lung in experimental pulmonary emphysema. J Appl Physiol. 1969 Jun;26(6):738–744. doi: 10.1152/jappl.1969.26.6.738. [DOI] [PubMed] [Google Scholar]
- Pushpakom R., Hogg J. C., Woolcock A. J., Angus A. E., Macklem P. T., Thurlbeck W. M. Experimental papain-induced emphysema in dogs. Am Rev Respir Dis. 1970 Nov;102(5):778–789. doi: 10.1164/arrd.1970.102.5.778. [DOI] [PubMed] [Google Scholar]
- Thurlbeck W. M. The internal surface area of nonemphysematous lungs. Am Rev Respir Dis. 1967 May;95(5):765–773. doi: 10.1164/arrd.1967.95.5.765. [DOI] [PubMed] [Google Scholar]
- Turner J. M., Mead J., Wohl M. E. Elasticity of human lungs in relation to age. J Appl Physiol. 1968 Dec;25(6):664–671. doi: 10.1152/jappl.1968.25.6.664. [DOI] [PubMed] [Google Scholar]