Fibrinolysis by rat mesothelial cells in vitro: the effect of mineral dusts at non-toxic doses.

Rat mesothelial cell cultures were shown to have considerable plasminogen dependent and independent fibrinolytic activity in vitro using an 125I fibrin degradation assay. At non-toxic doses of the mineral dusts titanium dioxide, quartz and crocidolite asbestos, as assessed by 51Cr release, the fibrinolytic activity of mesothelial cells was inhibited. Quartz had the greatest inhibitory effect and crocidolite asbestos had the least. These results suggests that inhibition of mesothelial cell fibrinolysis does not, on its own, explain pleural fibrosis due to toxic mineral dusts.