What is Cryosectioning?
Cryosectioning is a technique used in histology to prepare thin sections of biological tissues for microscopic examination. This method involves freezing the tissue samples and then cutting them into thin slices using a specialized instrument called a
cryostat. The frozen slices are then placed on glass slides for further examination or staining.
Why is Cryosectioning Important?
Cryosectioning is crucial in histology because it allows for rapid preparation of tissue samples. This is particularly beneficial for diagnostic purposes, especially in
clinical pathology, where quick results are often necessary. Additionally, cryosectioning preserves the antigenicity of tissues, making it an ideal technique for
immunohistochemistry and other applications that require intact protein structures.
1.
Sample Preparation: The tissue sample is first embedded in a medium, usually
OCT compound (Optimal Cutting Temperature compound), which provides support and stability during sectioning.
2.
Freezing: The embedded tissue is rapidly frozen using a cryostat, which maintains the tissue at a very low temperature (typically around -20°C to -30°C).
3.
Sectioning: The frozen tissue is then cut into thin sections, usually between 5 to 20 micrometers thick, using the cryostat.
4.
Mounting: The thin tissue sections are mounted on glass slides for subsequent staining and microscopic analysis.
- Speed: The process is much quicker than traditional paraffin embedding, allowing for rapid diagnosis.
- Preservation of Antigens: Freezing preserves the antigenic properties of tissues, making it ideal for immunohistochemical studies.
- Less Artifact Formation: The freezing process reduces the formation of artifacts compared to chemical fixation methods.
- Versatility: Cryosectioning can be used for a variety of tissue types, including fresh, fixed, or previously frozen tissues.
- Tissue Integrity: Rapid freezing can sometimes cause the formation of ice crystals, which can damage the tissue and affect the quality of the sections.
- Handling and Storage: Frozen sections are delicate and require careful handling. They also need to be stored at very low temperatures to prevent thawing and degradation.
- Limited Long-Term Storage: Unlike paraffin-embedded sections, cryosections are not ideal for long-term storage as they can degrade over time.
- Diagnostic Pathology: It is commonly used for rapid intraoperative diagnosis during surgeries to determine the nature of a lesion or tumor.
- Immunohistochemistry: The technique is ideal for studies that require the preservation of antigens for staining with antibodies.
- Research: Cryosectioning is used in research laboratories for studying the distribution and localization of specific proteins, nucleic acids, or other molecules within tissues.
- Frozen Section Analysis: This is a critical application in surgical pathology where quick decisions are needed regarding the surgical margins of excised tissues.
Conclusion
Cryosectioning is a valuable technique in histology that offers rapid and reliable preparation of tissue samples for microscopic examination. Its ability to preserve antigenicity and produce high-quality sections makes it indispensable for both diagnostic and research purposes. However, careful handling and appropriate storage conditions are essential to maintain the integrity of cryosections.
