In histopathology, fixation refers to the process of preserving biological tissue samples for microscopic examination. It involves treating the tissue with a fixative solution to prevent decay, maintain cellular structures, and stabilize the sample for further processing.
Fixation serves several purposes in histopathology:
1. Preservation: Fixation prevents tissue degradation and autolysis, which occurs when cellular enzymes break down the tissue after death. It stabilizes the tissue by cross-linking proteins and preserving cell and tissue structures.
2. Cellular and subcellular architecture: Fixation helps maintain the structural integrity of cells and subcellular components, such as organelles and nuclei. It prevents shrinkage, distortion, or loss of cellular details that can occur during subsequent processing steps.
3. Antigen preservation: Fixation helps preserve antigens within the tissue, making them accessible for immunohistochemical staining and other molecular techniques. It allows for the detection of specific molecules or markers within the tissue sections.
4. Inactivation of infectious agents: Fixation helps inactivate and render infectious agents non-infectious. This is particularly important when working with specimens that may contain pathogens, ensuring the safety of laboratory personnel.
Common fixatives used in histopathology include formaldehyde (usually as formalin), alcoholic solutions (e.g., ethanol), and glutaraldehyde. The choice of fixative depends on various factors, such as the type of tissue, intended histological analysis, and downstream applications.
After fixation, the tissue undergoes further processing steps, including dehydration, clearing, embedding in paraffin or resin, sectioning, and staining. These processes prepare the tissue for microscopic examination by pathologists, enabling the diagnosis of diseases and the evaluation of tissue morphology.
It’s important to note that the choice of fixative, duration of fixation, and other factors can influence the quality of histopathological analysis. Proper fixation techniques are crucial to ensure accurate and reliable results in histopathology.
In histopathology, fixation refers to the process of preserving biological tissue samples for microscopic examination. It involves treating the tissue with a fixative solution to prevent decay, maintain cellular structures, and stabilize the sample for further processing.
Fixation serves several purposes in histopathology:
1. Preservation: Fixation prevents tissue degradation and autolysis, which occurs when cellular enzymes break down the tissue after death. It stabilizes the tissue by cross-linking proteins and preserving cell and tissue structures.
2. Cellular and subcellular architecture: Fixation helps maintain the structural integrity of cells and subcellular components, such as organelles and nuclei. It prevents shrinkage, distortion, or loss of cellular details that can occur during subsequent processing steps.
3. Antigen preservation: Fixation helps preserve antigens within the tissue, making them accessible for immunohistochemical staining and other molecular techniques. It allows for the detection of specific molecules or markers within the tissue sections.
4. Inactivation of infectious agents: Fixation helps inactivate and render infectious agents non-infectious. This is particularly important when working with specimens that may contain pathogens, ensuring the safety of laboratory personnel.
Common fixatives used in histopathology include formaldehyde (usually as formalin), alcoholic solutions (e.g., ethanol), and glutaraldehyde. The choice of fixative depends on various factors, such as the type of tissue, intended histological analysis, and downstream applications.
After fixation, the tissue undergoes further processing steps, including dehydration, clearing, embedding in paraffin or resin, sectioning, and staining. These processes prepare the tissue for microscopic examination by pathologists, enabling the diagnosis of diseases and the evaluation of tissue morphology.
It’s important to note that the choice of fixative, duration of fixation, and other factors can influence the quality of histopathological analysis. Proper fixation techniques are crucial to ensure accurate and reliable results in histopathology.