Studies on thick sections of the nucleus of mouse Sertoli cells using an electron microscope operating at 300 kV

Examination of the three-dimensional structure of the Sertoli cell nucleus from mouse testes was performed under a high voltage electron microscope operating at 300 kV. Using an en bloc staining method along with fixation by osmium tetroxide and embedding in a mixture of Quetol 651, NSA and MNA, the structures of the nucleus were stained at a high contrast and satisfactory preservation was achieved, thus allowing their study at a high resolution within thick sections. Nuclear components could be observed clearly in 2-3 microns-thick sections of embedded material. Typical three-dimensional configurations of nucleoli and associated bodies were indicated. Thick sections permitted the observation that two or three pernucleolar bodies are usually attached on each side of the nucleoli or form a triangular shape of different sizes of vacuolar structures within the bodies. Stereoscopic observations also revealed overlapping of perinucleolar bodies and nucleoli and suggested the complexity of the components of perinucleolar and intranucleolar chromatin.