Suitable fixation condition for rat liver using microwave irradiation and its application to the immunohistochemistry of glutamate dehydrogenase.

Abstract

The rat liver was fixed with microwave (MW) fixation technique using a domestic microwave oven and glutamate dehydrogenase (GDH) was immunostained in the liver. The structure of liver was well preserved and formation of artificial vacuoles was hardly recognizable in the cytoplasm of liver cells when 2% paraformaldehyde containing 10% glucose and 0.025% CaCl2 was employed for a fixative and continuous MW irradiation was carried out for 30 sec. Granulated immunoreaction products of GDH were present in the cytoplasm of the liver cells and Kupffer cells. The intensity of the reaction was almost homogeneous among the cells. On the other hand, when the tissue was fixed with immersion fixation method, a diffuse reaction was seen in the cytoplasm of liver cells and intensity of the immunostaining was heterogeneous among the cells; the liver cells in zone 2 showed weaker reaction than those in zone 1 and 3. Immunoelectron microscopy revealed that GDH was located in the mitochondrial matrix along the inner membrane including crystal membrane.