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Parathyroid ultrastructure after aldehyde fixation, high-pressure freezing, or microwave irradiation
R Marti1, P Wild, E M Schraner
1Institute of Veterinary Anatomy, University of Zürich, Switzerland.
Summary
Parathyroid cell variants are an artifact of improper aldehyde fixation, not functional diversity. Optimized fixation methods like microwave irradiation or quick-freezing yield uniform parathyroid cell ultrastructure.
Area of Science:
- Endocrinology
- Cell Biology
- Histology
Background:
- Parathyroid cell variants are typically observed in parathyroid glands fixed using glutaraldehyde.
- These variants have been historically attributed to cyclic changes in parathyroid hormone secretion.
Purpose of the Study:
- To investigate the cause of parathyroid cell variants.
- To determine if cell variants result from fixation artifacts or functional diversity.
Main Methods:
- Comparison of fixation techniques: glutaraldehyde immersion, high-pressure quick-freezing with freeze-substitution, and microwave-assisted fixation.
- Evaluation of bovine and rat parathyroid glands using these methods.
- Ultrastructural analysis of parathyroid tissue.
Main Results:
- Glutaraldehyde fixation, especially immersion, induced cell membrane disruption and variants in rat parathyroids, while yielding uniformity in bovine parathyroids.
- High-pressure quick-freezing and microwave-assisted fixation resulted in a single cell variant in both species.
- Microwave irradiation with appropriate buffers and osmication provided excellent ultrastructural preservation.
Conclusions:
- Parathyroid cell variants are primarily an artifact of improper aldehyde fixation, not indicative of functional diversity.
- Optimized fixation protocols, including microwave-assisted methods and quick-freezing, are crucial for accurate ultrastructural studies of parathyroid glands.