alcian-blue and Alzheimer-Disease

Astrocytes play an essential role in the normal functioning of the nervous system and are active contributors to the pathogenesis of neurodegenerative diseases such as Alzheimer's disease (AD). Therefore, to comprehend the astrocytes and amyloid plaques relationship there is a need for imaging techniques providing simultaneous visualization of astrocytes using fluorescence and amyloid plaques revealed by transmitted light microscopy.. The possibility of simultaneous detection of astrocytes by immunocytochemistry (fluorescent) and amyloid plaques by cytochemical Alcian Blue (transparent) using confocal microscopy in 8-month-old 5хFAD mice samples shown.. The described method supposes performing astrocytes fluorescent labelling by GFAP or S100beta and amyloid plaques staining by Alcian Blue.. Proposed approach circumvents some limitations of fluorescence microscopy, such as weak fluorescence, low contrast, fluorophore broad excitation/emission profile and chemical instability.. The proposed technique provides high-quality resulting images of GFAP/s100beta- labelled astrocytes and Alcian Blue-stained amyloid plaques. These images are appliable for prospective qualitative and quantitative three-dimensional analysis due to the z-axis scanning. Moreover, it demonstrated the formation of stable Alcian Blue staining.

Topics: Alcian Blue; Alzheimer Disease; Amyloid beta-Peptides; Animals; Astrocytes; Mice; Mice, Transgenic; Microscopy, Confocal; Plaque, Amyloid; Prospective Studies

Previous studies have shown the basement membrane form of heparan sulfate proteoglycan (HSPG) known as perlecan, co-localized to beta-amyloid protein (A beta)-containing amyloid deposits in brains of patients with Alzheimer's disease (AD) and Down's syndrome. Although HSPG was localized to diffuse A beta plaques in hippocampus, amygdala, and neocortex, it is not known whether they are present in diffuse A beta plaques in cerebellum. In the present study, Alcian blue staining and immunocytochemical techniques were used to determine whether highly sulfated glycosaminoglycans (GAGs) and/or HSPG (perlecan) were also present in diffuse A beta plaques of cerebellum. Tissues from cases of AD were examined for the co-localization of highly sulfated GAGs, HSPGs, and A beta in diffuse plaques in cerebellum in comparison with hippocampus. Consecutive serial sections of AD brain tissue were stained or immunostained with 1) the modified Bielschowsky stain; 2) a polyclonal antibody directed against synthetic A beta (1-40); 3) Congo red; 4) Alcian blue (pH 5.7) with varying concentrations of magnesium chloride for identification of sulfated and highly sulfated GAGs; and 5) polyclonal and monoclonal antibodies recognizing either the core protein or a specific GAG epitope on perlecan. All cases (7 of 7) of AD contained diffuse A beta plaques in the cerebellum as identified by positive Bielschowsky staining and A beta immunoreactivity. None of these cases demonstrated positive Alcian blue staining (at 0.3 and 0.7 mol/L MgCl2), HSPG, or HS GAG immunoreactivity in the same diffuse cerebellar plaques on adjacent serial sections. However, Alcian blue staining, HSPG, and/or HS GAG immunoreactivity were observed in blood vessel walls, choroid plexus, and within Purkinje cells, suggesting that the techniques used were reliable and specific. In cerebellum, all plaques containing amyloid cores that were Congo red-positive were also positive for highly sulfated GAGs (by Alcian blue staining at 0.7 mol/L MgCl2) and HSPG (both core protein and GAG chain) immunoreactivity. Even though HSPG immunoreactivity was not present in cerebellar diffuse plaques, all cases (4 of 4) examined demonstrated HSPG (both core protein and GAG chain) immunoreactivity in diffuse A beta plaques in hippocampus. Therefore, by Alcian blue staining and immunocytochemical methods, highly sulfated GAGs and HSPGs are not present in A beta diffuse plaques in cerebellum. Since previous studies indicate that the cere

Topics: Aged; Aged, 80 and over; Alcian Blue; Alzheimer Disease; Amyloid beta-Peptides; Cerebellum; Female; Glycosaminoglycans; Heparan Sulfate Proteoglycans; Heparitin Sulfate; Hippocampus; Humans; Immunoenzyme Techniques; Male; Middle Aged; Proteoglycans