UPTAKE OF CONCENTRATED PERFLUOROCARBON EMULSIONS INTO RAT LYMPHOID-TISSUES

The effects of injecting (10 30 mL kg -1) either perfluorodecalin (FDC) emulsions of increasing phase fraction (20 60% w/v) or the commercial formulation, Fluosol, on lymphoid tissues have been studied for up to 7 days in male rats. Tissue weights increased by up to 123% (P < 0.05) in proportion with quantity of perfluorochemical (PFC) injected, with spleen responses consistently greater than those of the liver. PFC droplets recovered from these tissues at 72 h after injection of 30% (w/v) FDC emulsion (10 mL kg- 1) had mean diameters in the 1-10 mum range, with those from the spleen being larger than those from the liver. Recovered droplet diameters were considerably greater than freshly-prepared emulsion mean particle sizes (0.21-0.25 mum). These results suggest that coalescence of emulsion droplets following accumulation in lymphoid tissues is a pre-requisite for the eventual excretion of PFC vapour through the lungs.