[Morphological changes in the pleura caused by intracavitary administration of bleomycin]

We administered bleomycin to the intrapleural cavity of hamsters and observed acute and chronic histological changes of visceral pleura using light and electron microscopies. At 7 days after bleomycin challenge, we could find out the pleural thickening with infiltration of inflammatory cells, and then formation of pleural fibrosis at 28 days. However, in our study there was no abnormal findings of the lung parenchyma in morphology and intraalveolar cells, and lung distensibility. The dose (10-20 units/kg body weight) used in the study did not cause the abnormal changes in the parenchyma, although pleural thickening occurred. We suggest that intracavitary bleomycin administration is safely used for the treatment of malignant pleural effusion.