Journal of neuroscience research
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Peripheral nerves, subject to continuous elongation and compression during everyday movement, contain neuron fibers vital for movement and sensation. At supraphysiological strains resulting from trauma, chronic conditions, aberrant limb positioning, or surgery, conduction blocks occur which may result in chronic or temporary loss of function. Previous in vitro stretch models, mainly focused on traumatic brain injury modelling, have demonstrated altered electrophysiological behavior during localized deformation applied by pipette suction. ⋯ Peak inwards sodium currents and rectifying potassium current magnitudes were found to decrease in cells under stretch, channel reversal potentials were found to be left-shifted, and half-maximum activation potentials right-shifted. The threshold for AP firing was increased in stretched cells, although neurons retained the ability to fire induced APs. Overall, these results point to ion channels being damaged directly and immediately by uniaxial strain, affecting cell electrophysiological activity, and can help develop prevention and treatment strategies for peripheral neuropathies caused by mechanical trauma.
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Spinal cord injury (SCI) is a devastating neurological disorder, but few drugs have proven to be effective for its treatment. Neuroinflammation exaggerates the secondary injury subsequent to trauma. Emerging evidence suggests that melatonin may help protect neural tissue against secondary injury after SCI, but the underlying mechanisms remain elusive. ⋯ Melatonin increased the number of CD206+ and Arg1+ cells, decreased the number of CD16+ and iNOS+ cells and reduced the levels of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) in the spinal cord tissue of female SCI rats. Current findings suggest that melatonin may inhibit pro-inflammatory responses and promote M2 polarization of microglial/macrophages in the spinal cord in the early stage of SCI, facilitating functional recovery. Accordingly, melatonin may represent a promising therapeutic candidate for acute SCI.