The effects of electrical stimulation on neurons and glia of the central nervous system

Abstract

Overview

This review paper investigates how both direct current (DC) and alternating current (AC) electrical stimulation (ES) affect cells of the central nervous system (CNS), examining their potential and current use as neurotherapeutic strategies. The discussion also explores the promise of combining ES with other treatments, and its growing role in modern clinical rehabilitation.

Approach

• Comprehensive review bridging basic research and clinical translation.
• 124 manuscripts identified via Google Scholar provided insights into ES effects on neurons and glia in various in vitro and in vivo models.

Findings

• DC Stimulation: Promotes axonal extension towards the cathode and causes axon retraction at the anode, which can limit regeneration.
• AC Stimulation: Alternates electrode polarity, enabling axonal extension in both directions, with effects dependent on intensity and duration of stimulation.
• Glial Response: ES—AC or DC—downregulates pro-inflammatory cytokine production and upregulates anti-inflammatory cytokines, favoring A2/M2 reactive states which are conducive to regeneration.
• Oligodendrocytes: DC and AC stimulation enhance oligodendrocyte precursor cell (OPC) differentiation, increasing myelin content and supporting axonal myelination.
• Combinatorial Approaches: ES combined with stem cell therapy, drug delivery, or electroactive biomaterials increases the efficacy of these interventions.
• Clinical Applications: Short sessions of ES can provide long-term improvements. Early clinical efforts target gait restoration, tremor reduction, and speech improvement in conditions like spinal cord injury, Parkinson’s Disease, and stroke.

Conclusion

ES is an evolving neurotherapeutic strategy showing promise for CNS-related diseases and injuries. In-depth understanding of ES effects on neurons and glia is vital for optimization of future clinical applications. Researchers, clinicians, and patients should be aware that electrical stimulation actively modifies central nervous system cellular environments, which directly links to health risks and benefits depending on stimulation parameters and patient context. All EMF exposure can modulate biological responses, underscoring the ongoing need for rigorous EMF safety evaluation.