Electrical stimulation enhances neuronal cell activity mediated by Schwann cell derived exosomes

Electrical stimulation (ES) therapy has good effects in patients with nervous system injury-related diseases. ES promotes nerve cell regeneration and stimulates Schwann cells to express neurotrophic factors. The incidence of stress urinary incontinence (SUI) among elderly people is increasing. Some studies suggest that damage to the pudendal nerve is closely related to the pathogenesis of SUI. It has also been found that pelvic ES can reduce SUI symptoms in a rat model of SUI caused by pudendal nerve injury. Clinically, pelvic floor electrical stimulation is effective in patients with mild to moderate SUI. These studies indicate that ES may ameliorate damage to the pudendal nerve and thus achieve the goal of SUI treatment, although the mechanism of action of this treatment remains unclear. Therefore, the purpose of the present study was to clarify the relationships among ES, neural cells and Schwann cells at the cellular level. We applied ES to nerve cells at 100 mV/mm or 200 mV/mm for 0, 0.5, 1, or 2 h to investigate changes in nerve cell activity. We then co-cultured the nerve cells with Schwann cells to explore the influence of single-culture and co-culture conditions on the nerve cells. Compared to non-ES, ES of the nerve cells increased their activity. Compared to those in single culture, co-cultured nerve cells exhibited an additional increase in activity. We also found that Schwann cell derived exosomes could promote the activity of nerve cells, with glutamate and calcium ions playing a potential role in this process. These results suggest that the mutual regulation of neural cells and Schwann cells plays an important role in the process by which ES ameliorates neurological function, which may provide a basis for subsequent studies.