Modulation of biphasic pattern of cortical reorganization in spinal cord transected rats by external magnetic fields

Abstract

Study Design: Animal Study Objectives: To investigate the efficacy of low frequency magnetic fields (ELF-MF) in modulating the biphasic pattern of cortical plasticity in rats with complete spinal cord injury (cSCI). Setting: Laboratory based study conducted in India. Method: Adult wistar rats received cSCI at T-13 followed by ELF-MF exposure for either 5 or 12 or 32 days to study biphasic pattern. A set of motor and sensorimotor behavioral tests, cortical electrical activity (electroencephalography), spinal cord lesion area and volume, and expression of neurotrophic factor (BDNF) and inhibitory molecule (Nogo-A) was observed and recorded at the three time points in motor and sensory cortical areas. Result: A significant (p≤0.01) functional recovery was evident in locomotor (BBB score), sensorimotor (allodynia using von Frey test) and motor (grip strength) tests, lesion volume and power spectrum of EEG waves after 32 days of ELF-MF. Though both SCI and SCI+MF rats exhibited characteristic biphasic pattern in the expression of Nogo-A and BDNF, but the level of expression was significantly altered in later group at day 32. Conclusion: A significant improvement in the expression of BDNF and decrease in Nogo-A in the cortical areas after ELF-MF exposure led to facilitation of motor and sensorimotor functions of the hindlimb in cSCI rats. It is concluded that external magnetic fields have the potential to regulate the expression of various cortical plasticity associated proteins, but the temporal pattern of expression is preserved after injury. Sponsorship: Not applicable