Time-Dependent Autolysis in Ex Vivo-Maintained Rat Tissue in Saline: A Descriptive Study and Practical Guidance for...

Area of Science:

• Histopathology
• Tissue Preservation
• Autolysis Studies

Background:

• Autolysis, or self-digestion, can significantly impair histopathologic assessment.
• Establishing reliable timelines for tissue degradation is crucial for accurate diagnostic interpretation.
• Current protocols lack specific guidance on optimal pre-fixation tissue handling times.

Purpose of the Study:

• To systematically map the progression of autolysis in various ex vivo rat tissues.
• To compare autolysis rates under room temperature versus refrigerated (4°C) conditions.
• To provide evidence-based, tissue-specific timelines for practical guidance in pathology.

Main Methods:

• Thirty-six Sprague-Dawley rats were euthanized, and major organs were collected.
• Tissues were stored in sterile saline at room temperature or 4°C for 0.5 to 16 hours.
• Samples underwent fixation in 10% neutral buffered formalin, followed by Hematoxylin and Eosin (H&E) staining and CD31 immunohistochemistry.

Main Results:

• Most rat tissues showed minimal autolysis within 2 hours at room temperature.
• Refrigeration at 4°C significantly delayed the onset and progression of autolysis.
• CD31 antigenicity remained detectable in most tissues up to 16 hours, except in the intestine, indicating potential compromise in advanced autolysis.

Conclusions:

• This study establishes clear, tissue-specific timelines for autolytic changes in rat tissues.
• Refrigeration effectively extends the window for tissue preservation before fixation.
• The findings offer valuable guidance for pathologists handling tissues requiring temporary saline storage, especially for immunohistochemical analysis.