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Traumatically induced altered membrane permeability: its relationship to traumatically induced reactive axonal change
E H Pettus1, C W Christman, M L Giebel
1Department of Anatomy, Virginia Commonwealth University, Richmond.
Journal of Neurotrauma
|October 1, 1994
Summary
Mild to moderate traumatic brain injury (TBI) can alter axolemmal permeability. Moderate TBI caused axonal swelling and neurofilament changes, unlike mild TBI, indicating complex injury pathways.
Area of Science:
- Neuroscience
- Pathology
- Cell Biology
Background:
- Severe traumatic brain injury (TBI) is linked to axolemmal alterations.
- The impact of mild to moderate TBI on axolemmal integrity remains less understood.
Purpose of the Study:
- To investigate whether mild to moderate TBI causes changes in axolemmal permeability.
- To characterize the early cellular and molecular responses to axonal injury.
Main Methods:
- Adult cats received intrathecal horseradish peroxidase (HRP) infusions.
- Mild to moderate fluid percussion injury was induced.
- Axonal changes and HRP penetration were assessed using light and electron microscopy at various time points (5 min to 3 h).
Main Results:
- Mild TBI induced neurofilament misalignment and axonal swelling but no HRP passage.
- Moderate TBI showed focal axolemmal permeability to HRP, accompanied by mitochondrial abnormalities and neurofilament compaction.
- Neurofilament disassembly was observed over 3 hours, indicating delayed reactive axonal changes.
Conclusions:
- Traumatic axonal injury involves distinct pathobiological mechanisms.
- Moderate TBI elicits altered membrane permeability and neurofilament compaction, leading to delayed axonal degeneration.
- Axonal injury is a complex process with varied responses depending on injury severity.