Perfusion fixation of lungs for structure-function analysis: credits and limitations

Area of Science:

• Pulmonary research
• Tissue fixation techniques
• Microscopic anatomy

Background:

• Vascular perfusion is a common method for lung tissue fixation.
• The quality of preservation can be affected by the fixative solutions used.

Purpose of the Study:

• To reevaluate lung tissue preservation quality using vascular perfusion.
• To assess the effects of different fixatives on physiological variables and pulmonary microstructure.

Main Methods:

• Excised rabbit lungs were inflated and perfused under zone III conditions with various fixatives.
• Continuous monitoring assessed physiological variables.
• Electron microscopy analyzed pulmonary microstructure qualitatively and quantitatively.

Main Results:

• Isotonic glutaraldehyde caused significant edema, increasing perfusion pressure and lung weight.
• Adding glutaraldehyde to isotonic buffer solutions (510 mosM) prevented edema.
• Glutaraldehyde alone did not eliminate lung tissue's retractive force.
• Sequential perfusion with osmium tetroxide and uranyl acetate, or glutaraldehyde (510 mosM) followed by these, yielded satisfactory results.

Conclusions:

• Optimal lung tissue fixation for studying alveolar and capillary architecture can be achieved with sequential perfusion.
• Hyperosmotic fixatives may cause cell shrinkage, impacting volume measurements.