Analysis of Antigen-induced Pulmonary Morphologic Changes in Sensitized Rats

Kim, Sung Won; Sul, Mi Young

Abstract

PURPOSE: Challenge of asthmatic patients by means of inhalation of allergens may produce both an early and a late asthmatic reaction. This Study was designed to understand th late-phase asthmatic reaction animal models of asthma and to using facilitate basic pathophysiologic research relevant to this clinical disorder.
METHODS
We examined light microscopic and transmission electron microscopic pulmonary morphology of experirnentally allergen-induced asthmatic model of Sprague-Dowley rat to get more precise and time-ordered morphologic changes. The animals were sensitized and induced by ovalbumin with aluminum hydroxide and Pertussis vaccine as adjuvants.
RESULTS
The morphologic changes of early reaction were identified in the group sacrificed at 15 minute after induction. The major change was noted in bronchial epithelium revealed as cytologic vacuolization and desquamation into the lumina. There were no identifiable changes in bronchial smooth muscle and no increased infiltration of eosinophils in the lung. The late reaction was identified in the group sacrificed at 4 hours after induction. The major changes were increased infiltration of eosinophils in the bronchial and bronchiolar mucosa and submucosa, increased deposition of collagen beneath the bronchial subepithelial basement membrane, and morphologic changes of bronchial smooth muscle layer. The thickness of the bronchial smooth muscle layer were increased and the smooth muscle cell showed nuclear contraction, increased numbers of mitochondria near the nuclei, irregular distribution of actin filaments in the cytoplasm and focal ballooning of the cytoplasm. Smooth muscle was the most pronounced in the group sacrificed 1 week after induction. The group of sensitization only revealed no identifiable morphologic changes compared with the control group. The group of induction only showed increased infiltration of eosinophils and increased numbers of perinuclear mitochondria in smooth muscle cells, and which features were similar but milder than sensitization and induction group.
CONCLUSION
This study will help us to understand time-ordered precise histologic changes of allergic airway inflammation.