Clearance of Inhaled Potassium Octatitanate Whisker from Rat Lungs

Clearance of Inhaled Potassium Octatitanate Whisker from Rat Lungs: Hiroshi YAMATO, et al. Department of Environmental Health Engineering, University of Occupational and Environmental Health, Japan—The clearance rate of inhaled man-made fibers (MMFs) is one of the important factors for predicting health hazards in human. Potassium octatitanate whisker is a newly developed MMF in Japan with strong resistance to heat and chemicals. Two types of commercially sold potassium octatitanate whisker were used in this study. In order to examine the rate of clearance of this whisker, rats were exposed to whisker aerosol for 4 weeks and the rate of clearance of inhaled whiskers from rat lungs was examined in terms of the fiber mass clearance rate and dimensional change in whiskers. The decrease in fiber mass retained in rat lungs was expressed with a two-compartment model. As for the dimensional change in whiskers, no decrease was observed in diameter and no surface change due to dissolution was detected over the 12-month observation period. Macrophage mediated clearance was thought to be the main mechanism for the clearance of potassium octatitanate whiskers. (J Occup Health 2002; 44: 34–39)