Nerve cells detect and respond to electric field stimulation and extrinsic chemical guidance cues during development and regeneration; therefore, the development and optimization of an approach for functional neuronal regeneration are necessary for a nerve injury. In this study, we proposed using electric field stimulation to repair a nerve injury triggered by serious mechanical stretch loading. A device that provides continuous mechanical stretch and constant electric field stimulation was designed. Primary dissociated spinal cord neurons were stimulated by mechanical stretch (tensile strain 2.5–10%) at different times (1, 4, 8, and 12 h) to set up a moderate nerve injury model. Stimulated samples were evaluated with respect to cell viability, density, and axonal elongation by the MTT and immunofluorescence assays. The results indicated that mechanical stretch (S, 5% tensile strain, 4 h) caused moderate axonal injury, resulting in significant loss of cell viability and a decrease in cell density. However, injured spinal cord neurons became viable after electric field stimulation (E, 33 mA/m2, 4 h) in the fluorescein diacetate assay. In addition, neuronal viability, density, and elongation increased significantly after electric field stimulation compared with those of stretch-injured neurons. Moreover, electric field stimulation significantly activated the axonal guidance cues Netrin-1 and deleted in colorectal cancer (DCC) receptor expression compared with the stretch-injury group. These results indicate that electric stimulation activates synergistic guidance cues of expression to improve axonal growth relevant to nerve injuries. Our study provides new insight into neuronal regeneration.
Electric field Mechanical stretch Axonal guidance growth Netrin-1 DCC Spinal cord neurons
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We thank Michael Anderson for our English editing.
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
This article does not contain any studies with human participants performed by any of the authors.
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.
Informed consent was obtained from all individual participants included in the study.
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