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Updated: Sep 26, 2026
Identifying Microglia and Peripheral Infiltrating Macrophages in the Injured Spinal Cords Using Flow Cytometry
Published on: June 24, 2025
The effect of an applied electric field on macrophage accumulation within the subacute spinal injury
Loren J. Moriarty1, Richard B. Borgens
1Center or Paralysis Research, Department of Basic Medical Sciences, Purdue University, West Lafayette, Indiana, USA.
Abstract:
Macrophages are implicated to play a substantive role in the acute inflammatory reaction to CNS insult in the delayed progressive secondary damage to parenchyma, espacially myelin. When placed in an electrical field in vitro, macrophages show directed pseudopodial extensions and migrate towards the positive pole (anode). We have evaluated if ED1 positive macrophage accumulations in rat spinal cord injuries were affected by the applied extracellular voltage, comparing their numbers to a sham treated group. Our hypothesis was that the applied voltage may reduce the concentration of phagocytes in the central injury and thus reduce the level of secondary damage produced by them. The applied voltage gradient did not alter the number or density of macrophage accumulations in the three week lesion, nor is there any difference in the degree of cavitation between control and experimental groups.
Insights
Applying electrical voltage to spinal cord injuries did not alter macrophage accumulation or secondary damage. This study investigated electrical field effects on macrophages, finding no significant impact on phagocyte concentration or lesion severity in rats.
Area of Science:
- Neuroscience
- Immunology
- Biomedical Engineering
Background:
- Macrophages play a key role in central nervous system (CNS) inflammation and secondary damage after injury, particularly affecting myelin.
- In vitro studies show macrophages exhibit directed migration towards an anode in an electrical field.
Purpose of the Study:
- To evaluate the effect of applied extracellular voltage on ED1-positive macrophage accumulations in rat spinal cord injuries.
- To determine if electrical stimulation can reduce phagocyte concentration in the injury site and mitigate secondary damage.
Main Methods:
- Rats with spinal cord injuries were subjected to an applied extracellular voltage gradient.
- Macrophage accumulations (ED1 positive cells) were quantified in the lesion site at three weeks post-injury.
- A sham-treated group served as a control for comparison.
Main Results:
- The applied voltage gradient did not significantly alter the number or density of macrophage accumulations in the three-week spinal cord lesions.
- No significant difference in the degree of cavitation was observed between the voltage-treated and control groups.
Conclusions:
- Extracellular voltage application does not appear to modify macrophage infiltration or the extent of secondary damage in spinal cord injuries.
- Further research is needed to explore alternative methods for modulating macrophage activity in CNS injury contexts.
