Recovery of Particles from the Pleural Cavity Using Agarose Casts: A Novel Method for the Determination of Fiber Dose to the Rat Pleura

Abstract

A method to quantitatively recover fibers from the rat pleural cavity was developed. Rats were treated with a known number of glass fibers by intrapleural instillation. Free and cell-associated fibers in the pleural cavity were trapped within an agarose gel cast when an agarosel/detergent solution was instilled into the pleural cavity and allowed to harden. This cast was removed and liquefied, and the fibers were collected by centrifugation and quantitated by phase microscopy. Histologic examination of the pleural surfaces revealed specific lysis of the overlying mesothelial cells, with sparing of the subadjacent alveoli. Approximately 90% of the fibers were recovered from the pleural cavity when 1 × 10³ to 1 × 10⁶ fibers were instilled. The number of fibers present at specific locations, on the order of 0.5-1 mm² in area, of the pleura was also determined following the instillation of fibers. Fibers were found at all sites sampled and were found more frequently in association with the parietal surfaces. This method should prove useful in addressing various data gaps in fiber dosimetry.