Fixation of tissue

Fixation of tissue

Fixation of tissue Through this process, the cells and muscles are preserved in such a way that no changes in their structure occur during chemical factors and they remain in their original state. The chemicals used in this process are called Fixative.

To get better results from a good fixative, the sample taken for examination must be fresh. And only a piece of it about a centimeter thick and no bigger than that will not allow the Fixative to embed. The name of the fixative used is Formalin. It is known as Formaldehyde. 10% of it is used for this work which is done in normal saline.

Here are the main steps and considerations involved in tissue fixation:

1. Choice of Fixative: Different fixatives are used depending on the type of tissue and the purpose of the examination. Common fixatives include formaldehyde (often used as a 10% formalin solution), glutaraldehyde, and alcohol-based solutions.

2. Fixation Process:

   • Immersion: The tissue is immersed in the fixative solution. The volume of the fixative should be at least 10-20 times the volume of the tissue.
   • Perfusion: This technique involves perfusing the fixative through the blood vessels, commonly used for whole organs or large tissue samples.

3. Duration: The duration of fixation depends on the size and type of tissue and the fixative used. It typically ranges from a few hours to overnight.

4. Temperature: Fixation is usually carried out at room temperature, but in some cases, it might be performed at lower temperatures to slow down enzymatic activities.

5. Post-Fixation: After fixation, tissues may require washing to remove excess fixative. This is typically done with a buffer solution such as phosphate-buffered saline (PBS).

6. Storage: Fixed tissues can be stored in the same fixative solution or transferred to a storage solution (e.g., 70% ethanol) until further processing.

A good fixative has the following properties:

• Prevents muscle and visceral human organs from decaying.
• Keeps the tissue in its original condition and the starch in it also keeps the protein and fat in a safe condition.
• A good fixative preserves the tissue and protects it from damage in other processes of dyeing.
• Maintains tissue volume.
• Tissue (Tissue) is also helpful in coloring.