IN-VITRO EFFECTS OF LARGE AND SMALL GLASS-FIBERS ON RAT ALVEOLAR MACROPHAGES

The objective of this study was to explore the use oi alveolar macroph age culture to evaluate the cytotoxicity of two glass fiber materials, a building insulation fiberglass (a relatively long and thick fiber) and a glass microfiber (a short and thin fiber). Alveolar macrophages were obtained from male Sprague-Dawley rats by bronchoalveolar lavage and were cultured with varying fiber concentrations for up to 3 d. Fib er toxicity was assessed by assaying cell viability membrane integrity , and phagocyte function. The microfibers exhibited a concentration-de pendent cytotoxicity shown by the loss of cell viability and function. The building insulation fiberglass had little effect on cell viabilit y and did not change macrophage function in this assay system. The res ults of this study show that short and thin glass fibers are more toxi c than long and thick fibers in vitro, supporting a role of fiber dime nsion in toxicity.