Myelination is a process whereby glial cells identify, adhere, wrap and enclose axons to form a spiral myelin sheath.OBJECTIVE:
To investigate the effects of action potential-simulated weak electric fields on myelination in the central nervous system.DESIGN AND SETTING:
This single-sample observation study was performed at the 324 Hospital of Chinese PLA.MATERIALS:
Two 5 μ m carbon fibers were provided by the Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. One Sprague Dawley rat, aged 1 day, was used.METHODS:
Cerebral cortex was harvested from the rat to prepare a suspension [(1–2)×105/mL] containing neurons and glial cells. To simulate the axon, carbon fibers were placed at the bottom of the neuron-glial cell coculture dish, and were electrified with a single phase square wave current, 1×10−2, 1×10−3, 1×10−4, and 1×10−5 seconds, 1 Hz, 40 mV, and 10 μ A, 30 minutes each, once a day for 10 consecutive days to simulate weak negative electric fields during action potential conduction.MAIN OUTCOME MEASURES:
Glial cell growth and wrapping of carbon fibers were observed by phase contrast microscopy and immunohistochemistry.RESULTS:
On culture day 7, cell groups were found to adhere to negative carbon fibers in the 1×10−3 seconds square wave group. Cell membrane-like substances grew out of cell groups, wrapped the carbon fibers, and stretched to the ends of carbon fibers. Only some small and round cells close to negative carbon fibers were found on culture day 12. In the 1×10−4 and 1×10−3 seconds square wave groups, the negative carbon fibers were wrapped by oligodendrocytes or their progenitor cells.CONCLUSION:
The local negative electric field which is generated by action potentials at 1×(10−4-10−3) seconds, 40 mV can directly initiate and participate in myelination in the central nervous system.