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Changes in neuronal mRNAs induced by a local inflammatory reaction
1Division of Neurosurgery, McGill University, Montreal, Canada.
Journal of Neuroscience Research
|May 1, 1995
Summary
Injection of Corynebacterium parvum into dorsal root ganglia triggers inflammation and alters neuronal gene expression. Macrophages appear to sustain sensory neuron responses following nerve injury, promoting regeneration.
Area of Science:
- Neuroscience
- Immunology
- Molecular Biology
Background:
- Injection of Corynebacterium parvum into the dorsal root ganglion (DRG) induces a macrophage-dominated inflammatory response.
- This inflammatory response has been previously shown to enhance the regeneration of central axons in primary sensory neurons.
Purpose of the Study:
- To analyze neuronal mRNA modifications following C. parvum injection into the DRG.
- To investigate the role of macrophages in sensory neuron responses to nerve injury and regeneration.
Main Methods:
- In situ hybridization was used to analyze neuronal mRNA levels.
- Specific mRNAs investigated included growth-associated protein (GAP-43), c-jun, and calcitonin gene-related peptide (CGRP).
Main Results:
- Neuronal concentrations of GAP-43 and c-jun mRNAs increased after C. parvum injection, similar to axotomy responses.
- Calcitonin gene-related peptide (CGRP) mRNA levels increased in a subpopulation of sensory neurons post-injection, contrasting with its decrease after axotomy.
Conclusions:
- The findings support the hypothesis that macrophages accumulating in the DRG after nerve injury sustain sensory neuron responses.
- Macrophages may play a crucial role in promoting nerve regeneration by modulating gene expression in sensory neurons.