Histopathologic Study on the Effect of Tracheal Mucosa after Inhalation of O-Chlorobenzylidene Malononitrile(CS) in the Rats

Lee, Hyung Seok; Kim, Hyun Soo; Kim, Joo Mook; Kim, Kyung Rae; Ahn, Kyung Sung

Abstract

This study was undertaken to investigate the histopathological change in the tracheal mucosa of rats by light microscope following acute exposure to ortho-chlorobenzylidene malononitrile(CS). 2.0g/m3 of CS was inhalated to experimental rats for 20 minutes per day during 3 days in a plastic chamber. The experimental animals were sacrificed at 12 hours, 24 hours, 3 days, and 5 days after CS gas exposure. Specimens were obtained from upper most part of tracheal mucosa of the rats. After H and E stain and PAS stain were performed, all specimens were observed by light microscope. The result were as follows: 1) At 12 hours after exposure , there were some cilia destruction, widening of lamina propria, and infiltration of inflammatory cells in subepithelial layer. Epithelial lining and goblet cells were well preserved. 2) At 24 hours after exposure, epithelial lining and basement membrane were destructed and goblet cells were decreased in number. Infiltration of inflammatory cells in subepithelial layer were as sustained and vascular congestion was observed. 3) At 3 days after exposure, regeneration of epithelial layer, goblet cells, and basement membrane were identified. In subepithelial layer, a few inflammatory cells were infiltrated. 4) At 5 days after exposure, intact epithelial layer and numerous normal goblet cells were appeared. Lamina propria was narrowed and no inflammatory cells were in subepithelial layer. The results suggested that the tracheal mucosa of the rats shows a siginificant degenerative change after acute exposure to ortho-chlorobenzylidene malononitirile. However, it was temporary and reversible change.