Cortical electrical stimulation promotes neuronal plasticity in the peri-ischemic cortex and contralesional anterior horn of cervical spinal cord in a rat model of focal cerebral ischemia

Abstract

Purpose: This study evaluated the effect of cortical electrical stimulation (CES) on function recovery, dendritic plasticity, astrogliosis, and neuron recruitment in the peri-ischemic cortex (PIC) and contralesional anterior horn of cervical spinal cord (CSC) in a rat model of focal cerebral ischemia.

Materials and methods: Rats were pre-trained on single pellet retrieval task, then received focal ischemic lesions and electrodes implantation. Seven days after surgery, rats received CES (CES group) or no stimulation (NS group) during 18 days of training. Behavior data on stimulation days 2, 4, 6, 8, 10, 12, 14, 16 and 18 were pooled for use. Immunohistochemical investigations for microtubule-associated protein 2 (MAP-2), glial fibrillary acidic protein (GFAP) and neuronal nuclei antigen (NeuN) were performed.

Results: Rats in CES group showed greater functional recovery of the impaired forelimb compared to the NS group. Moreover, the functional improvement coincided with a significant increase in MAP-2-immunoreactive dendritic surface density in PIC and CSC (P=0.011; P=0.005, respectively). CES group had a significant decrease in GFAP-immunoreactive astrocytic surface density in PIC and CSC (P=0.039; P=0.013, respectively). In the immunoassaying of NeuN, there was no significant difference between the two groups in PIC and CSC (P=0.834, P=0.782, respectively).

Conclusion: CES can promote dendritic plasticity and reduce astrogliosis in the PIC and CSC in a rat model of focal cerebral ischemia. CES is still an appealing method for post-stroke rehabilitation provided that viability of pathways is evaluated presurgically.