Compensation for injury potential by electrical stimulation after acute spinal cord injury in rat

Injury potential, a direct current potential difference between normal section and the site of injury, is a significant index of spinal cord injury. However, its importance has been ignored in the studies of spinal cord electrophysiology and electrical stimulation (ES). In this paper, compensation for injury potential is used as a criterion to adjust the intensity of stimulation. Injury potential is modulated to slightly larger than 0 mV for 15, 30 and 45 minutes immediately after injury by placing the anodes at the site of injury and the cathodes at the rostral and caudal section. Injury potentials of all rats were recorded for statistical analysis. Results show that the injury potentials acquired after ES are higher than those measured from rats without stimulation and much lower than the initial amplitude. It is also observed that the stimulating voltage to keep injury potential be 0 remain the same. This phenomenon suggests that repair of membrane might occur during the period of stimulation. It is also suggested that a constant voltage stimulation can be applied to compensate for injury potential.

[1]  R B Borgens,et al.  An oscillating extracellular voltage gradient reduces the density and influences the orientation of astrocytes in injured mammalian spinal cord , 2001, Journal of neurocytology.

[2]  J Myklebust,et al.  Electrical field distribution within the injured cat spinal cord: injury potentials and field distribution. , 1994, Journal of neurotrauma.

[3]  R B Borgens,et al.  Enhanced spinal cord regeneration in lamprey by applied electric fields. , 1981, Science.

[4]  R B Borgens,et al.  Behavioral recovery induced by applied electric fields after spinal cord hemisection in guinea pig. , 1987, Science.

[5]  P Black,et al.  Spontaneous spinal cord "injury potential" in the rat. , 1985, Neurosurgery.

[6]  K. R. Robinson,et al.  The distribution of free calcium in transected spinal axons and its modulation by applied electrical fields , 1990, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[7]  P. Nelson,et al.  Oscillating field stimulation for complete spinal cord injury in humans: a phase 1 trial. , 2005, Journal of neurosurgery. Spine.

[8]  Luc Leybaert,et al.  Interstitial and tissue cations and electrical potential after experimental spinal cord injury , 2004, Experimental Brain Research.

[9]  M. Tymianski,et al.  Molecular mechanisms of calcium-dependent excitotoxicity , 2000, Journal of Molecular Medicine.

[10]  Kenneth R. Robinson,et al.  Electric field effects on human spinal injury: Is there a basis in the in vitro studies? , 2008, Developmental neurobiology.

[11]  R B Borgens,et al.  Large and persistent electrical currents enter the transected lamprey spinal cord. , 1980, Proceedings of the National Academy of Sciences of the United States of America.

[12]  Tao,et al.  Injury potentials associated with severity of acute spinal cord injury in an experimental rat model , 2011 .

[13]  R B Borgens,et al.  Voltage gradients and ionic currents in injured and regenerating axons. , 1988, Advances in neurology.

[14]  Alfred Reginald Allen,et al.  SURGERY OF EXPERIMENTAL LESION OF SPINAL CORD EQUIVALENT TO CRUSH INJURY OF FRACTURE DISLOCATION OF SPINAL COLUMN: A PRELIMINARY REPORT , 1911 .

[15]  Mahvash Zuberi,et al.  Large naturally-produced electric currents and voltage traverse damaged mammalian spinal cord , 2008, Journal of biological engineering.

[16]  B. Walters,et al.  Oscillating Field Stimulation in the Treatment of Spinal Cord Injury , 2010, PM & R : the journal of injury, function, and rehabilitation.

[17]  R B Borgens,et al.  An imposed oscillating electrical field improves the recovery of function in neurologically complete paraplegic dogs. , 1999, Journal of neurotrauma.

[18]  Borgens Rb,et al.  Voltage gradients and ionic currents in injured and regenerating axons. , 1988 .

[19]  L. A. Geddes,et al.  The discovery of bioelectricity and current electricity The Galvani-Volta controversy , 1971, IEEE Spectrum.

[20]  A. Blight,et al.  Control of membrane sealing in injured mammalian spinal cord axons. , 2000, Journal of neurophysiology.