A new staining method of astrocytes for paraffin section.

A new method of staining astrocytes in formation-fixed, paraffin-embedded sections was devised: (1) fix them in 5% mercuric chloride solution for 30 min to 1 h at 56 degrees C, (2) then place in 0.5% iodine alcohol for 5 min followed by placing in 0.5% sodium thiosulfate for 5 min, (3) immerse in 0.25% potassium permanganate for 3 min, (4) place in 2% oxalic acid for 2 min. (5) mordant in 2% iron alum for 45 s, and (6) place in 2% silver nitrate solution for 30 min. The next step is impregnation in ammoniacal silver solution for 10 -- 15 min at 56 degrees C, followed by reduction in neutral formalin and 2% iron alum, toning in 0.2% gold chloride, and fixing in 5% sodium thiosulfate. Pathological astrocytes of fibrillary and protoplasmic types were distincly demonstrated, although nerve cells and nuclei of oligodendrocytes and microglial cells were also faintly stained. Thus, the staining for paraffin sections is fairly selective for astrocytes in pathological states.