LR white post-embedding colloidal gold method to immunostain MBP, P0, NF and S100 in glutaraldehyde fixed peripheral nerve tissue.

A variety of immunocytochemical techniques are now widely used for the electron and light microscopic examination of biological samples. They are employed routinely for investigating the role of certain proteins in nervous tissue. Immunoelectron microscopic studies require the tissue to be fixed and embedded in a solid support, which may disrupt cellular structures and destroy crucial antigens. A technique of post-embedding with LR white resin has been developed, and it has been shown that certain antigens tolerate fixation with glutaraldehyde. In this study, we optimized a previous post-embedding method using low-water-miscible low-temperature embedding resin (LR white) to immunostain MBP, P0, NF and S100 proteins in peripheral nerves fixed with a relatively high concentration of glutaraldehyde found to be compatible with the morphology of normally compacted nerve fibers from humans and adult animals. The main difference in the procedures described here from previous ones is the elimination of vibratome sectioning, rendering this immunostaining technique more accessible to neuropathological laboratories using standard equipment for the ultrastructural study of peripheral nerves. It may prove of value for localization and quantification of these proteins in normal and pathological conditions.