Changes in the Pleural Cavity by Pleurodesis Using Talc or OK-432: An Experimental Study
To define the changes in the pleural cavity after pleurodesis induced by talc or OK-432. A total of 30 rats were divided into three groups: a normal saline group (control group, n = 10), a group administered 400 mg/kg talc (talc group, n = 10), and a group administered 0.3 KE/kg OK-432 (OK-432 group, n = 10). Pleural cavities were examined and scored on the 30th day after the intrapleural administration of each agent. Both the talc group and OK-432 group showed significantly higher macroscopic or microscopic pleurodesis scores than the control group (P < 0.05). Upon microscopic evaluation, the pleurodesis scores in the talc group were significantly higher than those in the OK-432 group (P < 0.01).The majority of the pleural thickness was found on the visceral pleura, and the parietal pleura was very thin. The thickness of the visceral pleura in the talc group was significantly higher than that in the OK-432 group (P < 0.005). Pathologically, the pleural thickening in the talc group consisted of fibrous tissue with injury of the pleural mesothelium, and talc particles were seen in the submesothelial fibrotic tissue and inside the alveoli. Talc pleurodesis induces more marked changes in the pleural cavity than OK-432-induced pleurodesis.