A specific immunofluorescence technique for the demonstration of vasogenic brain edema in paraffin embedded material

Serum proteins as constituents of vasogenic brain edema were visualized both macroscopically and microscopically applying a double layer immunofluorescence technique to paraffin embedded material derived from three experimental series: peritumorous edema following xeno-transplantation of glioma cells, edema after cerebral embolization with micropheres, and edema after unilateral MCA occlusion. Exclusively cats were used as experimental animals. The staining procedures resulted in selective green fluorescence of vessel contents as well as edema protein, which was demonstrable even macroscopically at times, where edema formation reaches a maximum in each experimental series. Microscopically, serum protein could be traced up to the end of observation time ranging from 1 to 4 weeks, where the specific fluorescence was related to cellular structures. As compared to other techniques employed in brain edema localization, immunostaining mainly offers the following advantages: avoidance of in vivo tracing, better structural resolution in paraffin than in freeze sections, high specificity and sensitivity in antigen localization.