Microwave fixation provides excellent preservation of tissue, cells and antigens for light and electron microscopy

Area of Science:

• Histology and Immunohistochemistry
• Biotechnology and Biomedical Engineering

Background:

• Traditional tissue fixation methods are time-consuming, potentially leading to degradation of cellular structures and antigens.
• There is a need for rapid and effective fixation techniques to preserve fine details and antigenicity for advanced research.

Purpose of the Study:

• To evaluate an ultrafast microwave fixation method for preserving light microscopic histology and fine structural details.
• To assess the preservation of cytoplasmic and membrane-bound antigens using this rapid fixation technique.
• To demonstrate the efficacy of microwave fixation for preserving specific biomolecules like rat mast cell chymase.

Main Methods:

• Utilizing microwave energy in combination with low concentrations of glutaraldehyde (0.05%) and formaldehyde (2.0%).
• Employing a specially designed microwave device for ultrafast fixation (26 ms for 1 cm³ blocks).
• Applying a commercially available microwave device for rapid fixation, followed by postembedding immunogold detection.

Main Results:

• Excellent preservation of light microscopic histology and fine structural details was achieved.
• A variety of cytoplasmic and membrane-bound antigens were successfully preserved.
• Granule-bound rat mast cell chymase was preserved and detected using immunogold labeling.

Conclusions:

• The ultrafast microwave fixation method offers rapid and effective preservation of biological specimens.
• This technique is suitable for preserving both histological details and antigenicity for subsequent analysis.
• Careful control of fixation parameters (specimen size, temperature, time, and postirradiation handling) is crucial for optimal results.