A microstructural study of oedema resolution.

The infusion model was used to investigate the resolution mechanism of vasogenic brain oedema. HRP dissolved in autoserum was infused into the white matter of cats. The infused protein in the oedema fluid seemed not only to be absorbed by pinocytosis or phagocytosis, as has been reported previously, but also to be quickly washed out via the perivascular space of the post-capillary venules. Smaller molecules such as HRP moved faster than serum albumin in these spaces after the infusion pump was turned off. Rapid flow of extracellular fluid via the perivascular space may play an important role on the resolution process of vasogenic brain oedema by accelerating diffusion.