Postmortem changes in stereological parameters of cerebral neurons

Area of Science:

• Neuroscience
• Cell Biology
• Pathology

Background:

• Neuronal morphology changes are crucial for understanding brain aging and disease.
• Postmortem changes can affect cellular structures, complicating interpretation.

Purpose of the Study:

• To stereologically investigate neuronal form and size changes in cats postmortem.
• To compare these changes with human cerebral cortex tissue.
• To clarify the nature of "dark neurons" and their potential artifactual origin.

Main Methods:

• Stereological investigation of neuronal surface area (Ai), perimeter (LPi), and formfactor (fi) in cat cerebral cortex.
• Intravital and postmortem analysis at 30 seconds, 5 hours, and 22 hours.
• Comparison with deep-frozen and formalin-fixed human cerebral cortex.

Main Results:

• Cat neurons exhibited swelling and metachromasia 30 seconds postmortem, resolving with autolysis.
• Swelling linked to circulatory disturbances; metachromasia associated with increased acid phosphatase.
• "Dark neurons" observed in human cortex were identified as fixation artifacts.

Conclusions:

• Early postmortem changes in neuronal morphology are significant and dynamic.
• Lysosomal activity and circulatory issues play roles in early postmortem neuronal alterations.
• Neuronal size and form analysis can aid in understanding pathological brain aging and neurodegeneration.