Experimental model resembling the histological pattern of usual interstitial pneumonia and reinforcing the epithelial injury as pathway

The present experimental model in mice was developed to confront the histopathological features with that of the idiopathic pulmonary fibrosis (IPF)/usual interstitial pneumonia (UIP), as we suppose both are caused by the injury of type II pneumocyte (TIIp) and by the increase of collagen system. Material and methods: Twenty male Balb/c mice are injected ip with 400mg/kg of butylated hydroxitolueno (BHT) and kept breathing for six days at a 70% oxygen atmosphere. The mice were killed after one month. The lungs were fixed and stained by Hematoxylin & Eosin and imunofluorescence for collagen I and III. Also, TUNEL and electron microscopy were used to evaluate the epithelial apoptosis index. We used 5 balb/c mice as controls. Results: Pulmonary specimens of this model confirmed UIP pattern, such as progressive increase of interstitial deposition. They showed significant increase of collagen I and III deposition and significant increase of epithelial apoptosis when compared to control group (p<0.05).The apoptosis was more prominent in the TIIp observed by electron microscopy. ![Figure][1] Conclusion: This experimental model showed the same histopathological patterns of UIP, and also reinforced the increase of apoptosis TIIp after injury or apoptosis of these cells and collagen deposition as an early feature in the pathogenesis of IPF. Financial support: FAPESP CNPq. [1]: pending:yes