Collection, Embedding and Special Staining of Lung Samples
Introduction
Lung diseases are prevalent and can significantly impact an individual's quality of life. To understand these diseases better and develop effective treatments, scientists and healthcare professionals often study lung tissue samples. This article aims to shed light on the fundamental processes involved in collecting, embedding, and special staining of lung samples, crucial steps in the journey toward understanding lung health and disease.
Figure 1. Hematoxylin and eosin (H&E) staining of lung tissue sections.(Yu K, et al.; 2017)
Collection of Lung Samples
The process of collecting lung samples begins with careful planning and preparation. Typically, samples are obtained during medical procedures such as biopsies or surgeries. In some cases, autopsies may also provide valuable tissue samples for research purposes. Regardless of the source, it's essential to handle the samples with precision and care to preserve their integrity and ensure accurate analysis.
Once collected, the lung samples must be properly preserved to maintain their structural and molecular properties. This often involves immediate immersion in a suitable fixative solution, such as formalin, which helps prevent degradation and cellular changes. Proper fixation is crucial for preserving cellular architecture and facilitating subsequent analysis.
Embedding of Lung Samples
After fixation, the lung samples undergo embedding, a process that involves encasing them in a solid medium to facilitate handling and sectioning. The most common embedding medium used in histology is paraffin wax. To embed lung samples, they are dehydrated through a series of alcohol washes to remove water and then infiltrated with molten paraffin wax.
Embedding serves several purposes. First, it provides support to the tissue, allowing it to be thinly sliced for microscopic examination. Second, embedding helps preserve the cellular structure of the lung tissue, ensuring that it retains its original morphology during the subsequent staining and imaging processes.
Special Staining of Lung Samples
Once embedded, lung tissue samples are ready for special staining, a crucial step in histological analysis that enhances the visualization of specific structures or substances within the tissue. Special stains target various cellular components, such as proteins, carbohydrates, and nucleic acids, allowing researchers to identify specific cell types, pathological changes, or disease markers.
One commonly used special stain in lung histology is the Hematoxylin and Eosin (H&E) stain, which highlights the basic cellular structure of the tissue. Hematoxylin stains nucleic acids blue-purple, while Eosin stains proteins and other cytoplasmic structures pink. This dual staining technique provides valuable information about the cellular composition and organization of the lung tissue.
Other special stains used in lung histology include:
Periodic Acid-Schiff (PAS) stain: This stain highlights carbohydrates, making it useful for identifying glycogen, mucin, and fungal organisms within the lung tissue.
Masson's trichrome stain: This stain is valuable for visualizing collagen fibers and distinguishing between normal and fibrotic lung tissue.
Immunohistochemistry (IHC): While not a traditional stain, IHC involves using antibodies to detect specific proteins within the lung tissue. This technique is widely used to identify biomarkers associated with various lung diseases, such as cancer.
Conclusion
In summary, the collection, embedding, and special staining of lung samples are essential processes in histological analysis. These steps require careful attention to detail and adherence to established protocols to ensure the accuracy and reliability of the results. By studying lung samples using these techniques, researchers can gain valuable insights into the normal anatomy and pathological changes associated with lung diseases, ultimately contributing to the development of better diagnostic and therapeutic strategies.
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- Yu K, et al.; Effect of multiple cycles of freeze-thawing on the RNA quality of lung cancer tissues. Cell Tissue Bank. 2017, 18(3):433-440.
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