Long-term neurite orientation on astrocyte monolayers aligned by microtopography

Area of Science:

• Biomaterials Science
• Neuroscience
• Regenerative Medicine

Background:

• Neuronal connections are difficult to re-establish after spinal cord injury.
• Scar tissue impedes neurite orientation and outgrowth from the injury site.
• Oriented biodegradable polymer scaffolds offer potential for guiding neurite growth.

Purpose of the Study:

• To investigate the long-term (3 weeks) orientation of neuronal cells on grooved polycaprolactone micro-topographies covered by an astrocyte monolayer.
• To determine the efficacy of micro-topography in guiding neurite alignment through an astrocyte layer for spinal cord injury repair.

Main Methods:

• Culturing neuronal cells on grooved polycaprolactone scaffolds with varying dimensions, both directly and with an overlaid astrocyte monolayer.
• Assessing neurite alignment and survival over 3 weeks.
• Evaluating the potential for myelination by endogenous oligodendrocytes.

Main Results:

• Neurites showed significant alignment along grooved topographies buried under astrocytes for up to 3 weeks.
• Alignment was reduced compared to direct growth on topography, but neurons survived longer.
• Optimal alignment and myelination support were observed with 12.5 or 25 micrometer groove dimensions.
• Micro-topography can influence neurite alignment through an astrocyte layer, enabling long-term myelination.

Conclusions:

• Micro-topography can effectively guide neurite orientation through an astrocyte layer, crucial for spinal cord injury regeneration.
• Specific groove dimensions (12.5-25 micrometers) are optimal for sustained neurite alignment and support myelination.
• This study demonstrates a novel method for promoting nerve regeneration in spinal cord injuries using biomaterial scaffolds and glial cells.