Effects of electrical stimulation of the sciatic nerve on the expression of vascular endothelial growth factor in the hippocampus and on learning and memory in cases of chronic cerebral hypoperfusion / 中华物理医学与康复杂志

ABSTRACT

Objective:To explore how electrical stimulation of the sciatic nerve affects learning and memory in cases of chronic cerebral hypoperfusion and its mechanism.Methods:Thirty-two Sprague-Dawley rats were randomly divided into a normal group, a sham-operation group, a model group and a stimulation group, each of 8. In the model and stimulation groups a chronic cerebral hypoperfusion model was established using the modified 2-VO method. The stimulation group then received electrical stimulation of the sciatic nerve for 4 weeks. Afterward all of the rats′ learning and memory were tested using the Morris water maze. HE staining and immunohistochemistry were used to observe any morphological change in the hippocampus and the expression of neuron-specific enolase (NSE) and vascular endothelial growth factor (VEGF).Results:The model and stimulation groups demonstrated significantly longer escape latency, fewer platform crossing times and shorter target quadrant times than the normal and sham-ope-ration groups before the intervention. All of these indicators had improved after the intervention. According to the HE staining, neuronal damage in the hippocampus was aggravated significantly in the model group compared with the normal and sham-operation groups, while the degree of damage was reduced in the stimulation group. Moreover, the immunohistochemistry results suggested that the expressions of NSE and VEGF were reduced significantly in the model group compared with the normal and sham-operation groups, while in the stimulation group they had increased significantly compared with the model group.Conclusions:Electrical stimulation of the sciatic nerve can improve learning and memory in cases of chronic cerebral hypoperfusion, at least in rats. It is probably related to the increased expression of VEGF in the hippocampus.