ABSTRACT | PROTOCOL:
One of the hallmark pathologies associated with Alzheimer's disease (AD) is the conspicuous deposition of extracellular amyloid plaques within the forebrain. These plaques are primarily composed of aggregates of the A-beta peptide. Traditional methods for the histological localization of these plaques typically rely on the use of the tracers Congo Red or Thioflavin S. This study describes the characterization of a novel fluorescent histochemical probe, Amylo-Glo, for the high resolution and contrast localization of amyloid plaques in brain tissue sections. Potential advantages over conventional amyloid plaque stains such as Congo Red or Thioflavin S can be attributed to its unique chemical and spectral properties. Specifically, it results in a very bright blue UV excitable stain under physiological conditions that will not bleed through when illuminated with other filters. Its brightness makes it ideal for low magnification quantification studies, while its unique excitation/emission profile and mild staining conditions makes it ideal for combination with multiple immunofluorescent labeling studies.
Classification: Styrylbenzene derivative
Appearance: Yellow solution
Purity: Thin layer chromatography using alumina plates and a solvent system of ethanol and water (3:1) revealed the presence of two fluorescent isomers. No amount of starting material was detected.
Molecular Weight: 392
Excitation Peak: 334
Emission Peak: 533 nm - unbound, 438 nm when bound to amyloid
Filter system for visualizing: UV
Storage: The stock solution should be refrigerated at about 5℃.
Toxicity: Although the compound appears to be of low toxicity, it has not been extensively evaluated and therefore routine laboratory caution should be exercised. Not intended for human consumption.
Larry Schmued, James Raymick, William Tolleson, Sumit Sarkar, Yi-Hong Zhang, Ashlee Bell-Cohn, Journal of Neuroscience Methods, Introducing Amylo-Glo, a novel fluorescent amyloid specific histochemical tracer especially suited for multiple labeling and large scale quantification studies 2009 (2012) 120-126.
AMYLO-GLO STAINING PROCEDURE:
Amylo-Glo tissue was examined using an epifluoresent microscope with UV (Nikon UV-2A) filter cube. Excitation (325-375nm) Emission (400-450nm). It is not uncommon for Amylo-Glo to appear light yellow when examined by eye, yet appear a light blue color when photographed.
View Sample Photomicrographs