Cyclosporin-A treatment attenuates delayed cytoskeletal alterations and secondary axotomy following mild axonal stretch injury.

Abstract

Following central nervous system trauma, diffuse axonal injury and secondary axotomy result from a cascade of cellular alterations including cytoskeletal and mitochondrial disruption. We have examined the link between intracellular changes following mild/moderate axonal stretch injury and secondary axotomy in rat cortical neurons cultured to relative maturity (21 days in vitro). Axon bundles were transiently stretched to a strain level between 103% and 106% using controlled pressurized fluid. Double-immunohistochemical analysis of neurofilaments, neuronal spectrin, alpha-internexin, cytochrome-c, and ubiquitin was conducted at 24-, 48-, 72-, and 96-h postinjury. Stretch injury resulted in delayed cytoskeletal damage, maximal at 48-h postinjury. Accumulation of cytochrome-c and ubiquitin was also evident at 48 h following injury and colocalized to axonal regions of cytoskeletal disruption. Pretreatment of cultures with cyclosporin-A, an inhibitor of calcineurin and the mitochondrial membrane transitional pore, reduced the degree of cytoskeletal damage in stretch-injured axonal bundles. At 48-h postinjury, 20% of untreated cultures demonstrated secondary axotomy, whereas cyclosporin A-treated axon bundles remained intact. By 72-h postinjury, 50% of control preparations and 7% of cyclosporin A-treated axonal bundles had progressed to secondary axotomy, respectively. Statistical analyses demonstrated a significant (p < 0.05) reduction in secondary axotomy between treated and untreated cultures. In summary, these results suggest that cyclosporin-A reduces progressive cytoskeletal damage and secondary axotomy following transient axonal stretch injury in vitro.

• Authors: J A Staal, T C Dickson, R S Chung, J C Vickers
• Journal: Developmental neurobiology (Dev Neurobiol) Vol. 67 Issue 14 Pg. 1831-42 (Dec 2007) ISSN: 1932-8451 [Print] United States
• PMID: 17702000 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Enzyme Inhibitors
• Nerve Tissue Proteins
• Cyclosporine
• Cytochromes c

Topics

• Animals
• Axonal Transport (drug effects)
• Axons (drug effects)
• Axotomy
• Cells, Cultured
• Cyclosporine (pharmacology)
• Cytochromes c (metabolism)
• Cytoskeleton (drug effects, physiology)
• Embryo, Mammalian
• Enzyme Inhibitors (pharmacology)
• Neocortex (cytology)
• Nerve Tissue Proteins (metabolism)
• Neurons (pathology)
• Perfusion (adverse effects)
• Rats
• Rats, Wistar
• Stress, Mechanical
• Time Factors