title: Axon Outgrowth of Rat Embryonic Hippocampal Neurons in the Presence of an Electric Field.
abstract: Application of an electric field (EF) has long been used to induce axon outgrowth following nerve injuries. The response of mammalian neurons (e.g., axon length, axon guidance) from the central nervous system (CNS) to an EF, however, remains unclear, whereas those from amphibian or avian neuron models have been well characterized. Thus, to determine an optimal EF for axon outgrowth of mammalian CNS neurons, we applied a wide range of EF to rat hippocampal neurons. Our results showed that EF with either a high magnitude (100 mV/mm or higher) or long exposure time (10 h or longer) with low magnitude (10-30 mV/mm) caused a neurite collapse and cell death. We also investigated whether neuronal response to an EF is altered depending on the growth stage of neuron cultures by applying 30 mV/mm to cells from 1 to 11 days in vitro (DIV). Neurons showed the turnover of axon outgrowth pattern when electrically stimulated between 4-5 DIV at which point neurons have both axonal and dendritic formation. The findings of this study suggest that the developmental stage of neurons is an important factor to consider when using EF as a potential method for axon regeneration in mammalian CNS neurons.
authors.affiliation: School of Engineering, ‡Center for Biomedical Engineering, and §Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States.
authors.forename: Kwang-Min
authors.initials: KM
authors.lastname: Kim
authors.affiliation: School of Engineering, ‡Center for Biomedical Engineering, and §Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States.
authors.forename: Sung Yeol
authors.initials: SY
authors.lastname: Kim
authors.affiliation: School of Engineering, ‡Center for Biomedical Engineering, and §Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States.
authors.forename: G Tayhas R
authors.initials: GT
authors.lastname: Palmore
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology*; D016923:Cell Death / Q000502:physiology; D049108:Cell Enlargement; D002478:Cells, Cultured; D004558:Electric Stimulation; D004574:Electromagnetic Fields; D006624:Hippocampus / Q000196:embryology / Q000502:physiology*; D007091:Image Processing, Computer-Assisted; D008853:Microscopy; D017207:Rats, Sprague-Dawley
keywords: Nerve regeneration; axon outgrowth; electrical stimulation; ionic currents; mammalian CNS