Early fibrogenicity of asbestos fibers in visceral peritoneum.

Different asbestos types and milled asbestos cement were inoculated intraperitoneally into mice. Mesenteric tissue (appendices epiploicae) was examined by transmission electron microscopy at different intervals between 2 h and 3 weeks after exposure to asbestos. As early as 2 h after asbestos administration, the investigated tissues exhibited focal mesothelial cell loss barring the basement membrane, which at some points was even disrupted. Severe cell damage, obviously caused by the mineral fibers, was discernible in the remaining mesothelial cells. At a later stage, the whole peritoneal sheet underwent inflammatory and diffuse fibrotic processes. The early surface irritation is due to the mechanical influence of the penetrating asbestos fibers. The results confirm our previously published findings with the scanning electron microscope that asbestos has distinct fibrogenic properties.