Quantitative analysis by in vivo imaging of the dynamics of vascular and axonal networks in injured mouse spinal cord

PNAS, 2009 · DOI: 10.1073/pnas.0900222106 · Published: June 9, 2009

Spinal Cord Injury Regenerative Medicine Neurology

Simple Explanation

This study used a special microscope to watch how nerves and blood vessels change in the spinal cords of living mice after an injury. The researchers looked at how nerve fibers try to regrow and how blood vessels respond to the damage. The images showed that nerve fibers initially sprout and try to regrow, even past the injury site. The number of blood vessels also increases for a short time. The study found that new blood vessels seem to help nerve fibers grow, but they don't guide them in a specific direction. This type of imaging could be helpful for studying brain diseases and testing new treatments because it allows scientists to see what's happening in the body over time.

Study Duration

4 months

Participants

24 adult transgenic Thy1GFP-M mice

Evidence Level

Not specified

Key Findings

1
Injured axons show early explorative sprouting, resulting in extensive regrowth until and past the lesion site within 2 months.
2
Blood vessel density was transiently up-regulated and most neurovascular interactions occurred within 2 weeks postinjury.
3
Neovessels exerted a potent growth stimulating action on neighboring sprouts, but no guidance effect due to their geometry and plasticity.

Research Summary

The study uses 2-photon microscopy to monitor vascular and axonal network changes in living mice after spinal cord lesion, observing regrowth of injured axons and transient upregulation of blood vessel density. It finds that neovessels stimulate axon growth but don't guide them, suggesting angiogenesis stimulation could be beneficial if reconnection depends on axon sprout density. The imaging approach shows promise for monitoring brain diseases and treatment efficacy, highlighting the dynamics of degeneration/regeneration in spinal cord axons and vascular networks.

Practical Implications

Therapeutic Angiogenesis

Stimulating angiogenesis post-SCI could enhance axon regeneration, potentially improving functional outcomes.

Monitoring Treatment Efficacy

The in vivo imaging technique allows for direct monitoring of treatment effects on axonal and vascular dynamics.

Understanding Neurovascular Interactions

Further research into the specific trophic factors released by blood vessels could lead to targeted therapies promoting axon regeneration.

Study Limitations

1
Limited penetration depth of the imaging technique.
2
The geometry and plasticity of blood vessels limit their guidance effect on regenerating axons.
3
The study focused on the dorsal column, which may not fully represent the complexity of SCI.

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