Experimental brain tumors and edema in rats. III. Peritumorous edema

In rats experimental brain tumors were produced by intracerebral implantation of a glioma cell clone. Peritumorous edema was investigated by light and electron microscopy, using exogenous tracers [human serum albumin (HSA), horseradish peroxidase] and immuno-histochemical methods for localization of endogenous serum proteins. An infiltration by serum proteins was observed in peritumoral grey and white matter. Peroxidase was found in pinocytotic vesicles of vascular endothelial cells, in pericytes and diffusely in the extracellular space. High concentrations of endogenous rat serum proteins and exogenous human serum albumin were also found in neurons of the grey matter and in oligodendrocytes of the white matter. A cellular uptake of extravasated proteins, therefore, may contribute to edema resolution.