Elastase-induced changes in lung function: relationship to morphometry and effect of drugs.

Area of Science:

• Pulmonary Medicine
• Pharmacology
• Toxicology

Background:

• Emphysema involves lung tissue destruction, often studied using animal models.
• Porcine pancreatic elastase (PPE) is an enzyme that degrades lung tissue.
• Understanding elastase-induced lung damage is crucial for developing emphysema treatments.

Purpose of the Study:

• To investigate the effects of porcine pancreatic elastase (PPE) on lung function and histology in rabbits.
• To evaluate the potential of dexamethasone and all trans retinoic acid (ATRA) in preventing or reversing PPE-induced lung damage.
• To establish PPE-induced lung injury as a model for assessing anti-emphysema drug efficacy.

Main Methods:

• Intratracheal administration of varying doses of PPE to New Zealand White rabbits.
• Assessment of dynamic lung compliance (C(dyn)) to measure lung function changes.
• Histological examination of lung tissue for emphysematous changes.
• Treatment with dexamethasone or ATRA before or after PPE administration.

Main Results:

• PPE caused a dose-dependent decline in C(dyn) within 24 hours, persisting for 56 days.
• Histological analysis confirmed emphysema in PPE-treated rabbits.
• Trypsin administration did not induce similar lung function or histological changes.
• Dexamethasone and ATRA failed to prevent or reverse PPE-induced lung dysfunction and emphysema.

Conclusions:

• Intratracheal PPE administration reliably induces emphysema and impaired lung function in rabbits.
• Glucocorticosteroids and ATRA are ineffective in mitigating PPE-induced lung injury.
• PPE-induced lung injury serves as a valuable model for evaluating therapeutic interventions for emphysema.