Amyloid is an amorphous extracellular eosinophilic substance that can be deposited in various tissues and organs, and the diseases caused thereby are referred to as amyloidosis. Amyloid is mainly composed of proteins, most of which are arranged in an antiparallel β-pleated sheet structure. Under an electron microscope, amyloid presents a fibrillary arrangement, appearing as a large number of unbranched extracellular filaments in pathological specimens, mostly arranged randomly. Histological methods for identifying amyloid include methyl violet staining, Congo red staining, and polarized light microscopy. Current research has demonstrated that the traditional methyl violet staining method has low sensitivity and poor specificity, whereas Congo red staining is a classic and effective approach. In 1922, Bennhold discovered that Congo red could be used for the identification of amyloid in vivo and applied this technique to tissue sections. Later, the method was modified by Highman, resulting in improved staining efficacy.
Amyloid Staining Solution (Highman Congo Red Method) is mainly composed of Highman Congo Red Staining Solution and Hematoxylin Staining Solution. This staining kit is simple to operate, features stable performance, and has been widely used in relevant research. This reagent is for research use only and is not suitable for clinical diagnosis or any other purposes.
A1508468
| Component | 3×50 mL | Storage |
| A1508468A | Highman Congo Red Staining Solution
| 50 mL | RT. Store in the dark.
|
| A1508468B | Alkaline Ethanol Differentiating Solution
| 50 mL | RT. |
| A1508468C | Hematoxylin Staining Solution
| 50 mL | RT. Store in the dark. |
Materials to be Prepared by User
10% neutral formalin, distilled water, graded ethanol, xylene or environment-friendly paraffin removal and clearing solution, neutral balsam
Procedure (for reference only)
1. Perform routine fixation, usually with 10% neutral formalin fixative, followed by routine dehydration and embedding.
2. Dewax paraffin sections with xylene or dewaxing and clearing solution and rinse them in distilled water; directly immerse frozen sections in distilled water. If necessary, remove pigments from the sections.
3. Immerse the sections in Highman Congo Red Staining Solution for 5-10 min.
4. Differentiate with Alkaline Ethanol Differentiating Solution for 3-10 s, immediately transfer the sections to water to terminate differentiation, and rinse with tap water.
5. Immerse the sections in Hematoxylin Staining Solution to stain cell nuclei for 1-2 min.
6. Rinse briefly with tap water, then transfer to distilled water for rinsing to achieve differentiation and bluing.
7. Conduct routine dehydration with graded ethanol, clear the sections with xylene or dewaxing and clearing solution, and mount them with neutral balsam.
Staining Results
Amyloid, elastic fibers, eosinophilic granules: Red
Cell nucleus: Blue
Precautions
1. Ensure thorough dewaxing of sections; otherwise, the staining effect will be compromised.
2. Store Alkaline Ethanol Differentiating Solution in a sealed container and use it as soon as possible after opening.
3. The differentiation time should be determined based on section thickness, tissue type, and the freshness of the differentiating solution. In addition, ensure sufficient rinsing time with tap water after differentiation.
4. The differentiation step with Alkaline Ethanol Differentiating Solution is critical. Immediately transfer the sections to water to terminate differentiation to prevent over-differentiation.
5. For your safety and health, wear a lab coat and disposable gloves during operation.
6. Use the reagent as soon as possible after opening to avoid affecting the results of subsequent experiments.
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