A model for long-term transgene expression in spinal cord regeneration studies

Area of Science:

• Neuroscience
• Gene Therapy
• Biotechnology

Background:

• First-generation adenoviral vectors are utilized for gene delivery.
• Spinal cord white matter presents unique challenges for gene delivery.

Purpose of the Study:

• To assess the suitability of first-generation adenoviral vectors for gene delivery into rat spinal cord white matter.
• To determine the impact of vector titer on transgene expression, tissue damage, and immune response.

Main Methods:

• Adult rats received injections of beta-galactosidase-expressing adenovirus at various titers (10^5 to 10^7 p.f.u.) into the spinal cord white matter.
• Transgene expression, axon degeneration, demyelination, astrocyte loss, and immune response were evaluated over time.

Main Results:

• High titers (≥10^6 p.f.u.) resulted in extensive transgene expression but severe tissue damage.
• Lower titers (≤10^5 p.f.u.) caused minimal axon degeneration and demyelination.
• beta-Galactosidase expression was detectable for at least 72 days.
• Immune response was minimal at 10^5 p.f.u. in PVG rats but prominent at higher titers or in AO rats, indicating strain and titer dependence.

Conclusions:

• First-generation adenoviral vectors can achieve moderate, long-lived transgene expression in the spinal cord with minimal tissue damage and immune response when used at appropriate titers in low-responder rat strains (e.g., PVG).
• This approach provides a suitable model for studying gene delivery effects in spinal cord injury models.