COMPARATIVE CHARACTERISTICS OF IMMUNCHISTOCHEMICAL AND ELECTRONIC MICROSCOPIC STRUCTURAL FEATURES OF THE BRAIN AND SPINAL CORD MENINGES

Abstract

The article presents data on the relationship between the expression of intermediate filament proteins and the ultrastructural features of the elements of the meninges of the brain and spinal cord and their surrounding structures.

Blocks of paraffin and epon-araldite were made after fixing pieces taken at the level of the meninges of the brain and spinal cord of six domestic ducks. For immunohistochemical studies of sections of paraffin blocks after heating in a microwave oven, the expression of intermediate filament proteins was detected by the avidin-biotin peroxidase method using diaminobenzidine as a chromagen and photographed under a Primo Star (Zeiss) light microscope. Ultrathin sections of araldite-epon blocks after staining were examined under a transmission electron microscope (JEM-1400 - Japan) and took electronograms. Although weak shading was mainly observed at the level of the dura mater, no expression of vimentin was detected in the arachnids and pia maters of the brain and spinal cord. Pansitokeratin was found to be expressed in the cytoplasm of leptomeningeal cells located in both layers of the arachnoid. It was found that unstained areas at the level of the reticular layer of arachnoid are ultrastructurally compatible with topographic decomposition of collagen fiber bundles. EMA expression was found only in cells of the arachnoid barrier cell layer with characteristic features of epithelial tissue. Expression of glial fibrillar acidic protein (GFAP) has been found at the locations of protoplasmic and fibrous astrocytes. The dependence of the level of GFAP expression on the ultrastructurally detected amount and density of intermediate filaments was recorded. IHC and electron microscopy in domestic ducks revealed that the superficial glial limiting membrane in the brain consists of single-layer protoplasmic astrocytes, and in the spinal cord pial processes of fibrous astrocytes. In conclusion, it should be noted that when evaluating the results of an immunohistochemical study, one should take into account the histological and ultrastructural features structures under study.