[Effect of scalp acupuncture on learning ability and hippocampal VEGF expression in chronic cerebral ischemia rats]

To observe the effect of scalp cluster-needle intervention on cognitive ability and hippocampal vascular endothelial growth factor (VEGF) expression in cerebral ischemia (CI) rats.

Forty Wistar rats were randomized into sham operation (sham), model, scalp-acupuncture and medication groups. Chronic CI model was established by occlusion of the bilateral common carotid arteries. Acupuncture needles were inserted into "Baihui" (GV 20) and its left and right points (2 mm beside GV 20) and manipulated leftward and rightward for 3 min at a frequency of about 200 times/min, retained for 30 min. The treatment was conducted once daily, for 4 weeks. For rats of the medication group, Nimodipine (1 mg/kg) was given to the animal by gavage, once a day, for 4 weeks. The rats' learning ability was measured by Morris water maze. Changes of hip-pocampal cellular morphology were observed by HE staining and light microscope, and hippocampal VEGF expression was detected by immunohistochemistry.

In comparison with the sham group, the escape latency of rats in the model group was prolonged significantly (P < 0.05), suggesting a decrease of learning ability after CI. Compared with the model group, the escape latency of both acupuncture and medication groups were reduced markedly after the treatment (P < 0.05). In comparison with the sham group, the number of VEGF immunoreaction (IR) positive cells in the model group was up-regulated significantly (P < 0.05), while compared with the model group, the numbers of both acupuncture and medication groups were increased further (P < 0.05). No significant differences were found between the acupuncture and medication groups in escape latency and VEGF expression levels (P > 0.05). HE staining showed that in the model group the hippocampal pyramidal cells were reduced in number, became vaguer in layers and nucleole, and got deformed in structure with karyopycnosis and disappearance of endochylema, and cavitation. These situations were relatively lighter in both acupuncture and medication groups.

Scalp acupuncture intervention can significantly improve CI rats' congnitive ability and pathological changes, which may be related to its function in increasing the expression of VEGF in the hippocampus.