摘要

BACKGROUND: Previous studies have demonstrated that acupuncture treatment could ameliorate impaired motor function, and these positive effects might be due to neural plasticity. OBJECTIVE: Myelin basic protein (MBP), microtubule-associated protein 2 (MAP2), growth-associated protein-43 (GAP-43), and synaptophysin (SYN) were selected as markers of neural remodeling, and expression of these markers was evaluated with regard to altered motor function following brain injury and acupuncture treatment.
DESIGN, TIME AND SETTING: A completely randomized experiment was performed at the Central Laboratory of Peking University First Hospital from November 2006 to May 2007.
MATERIALS: Twenty-four Sprague Dawley rat pups, aged 7 days, were selected for the present experiment. The left common carotid artery was ligated to establish a rat model of ischemic-hypoxic brain injury.
METHODS: All animals were randomly divided into three groups: sham operation, model, and electro-acupuncture treatment, with 8 rats in each group. Rats in the model and electro-acupuncture treatment group underwent establishment of ischemic-hypoxic brain injury. Upon model established, rats underwent hypobaric oxygen intervention for 24 hours. Only the left common carotid artery was exposed in rats of the sham operation group, without model establishment or oxygen intervention. The rats in the electro-acupuncture treatment group were treated with electro-acupuncture. One acupuncture needle electrode was inserted into the subcutaneous layer at the Baihui and Dazhui acupoint. The stimulation condition of the electro-acupuncture simulator was set to an amplitude-modulated wave of 0-100% and alternative frequency of 100 cycles/second, as well as frequency-modulated wave of 2-100 Hz and an alternative frequency of 3 cycles/second. Maximal current through the two electrodes was limited to 3-5 mA. The stimulation lasted for 30 minutes per day for 2 weeks. Rats in the sham operation and model groups were not treated with electro-acupuncture, but only fixed to the table for the same time period.
MAIN OUTCOME MEASURES: After 2 weeks stimulation, expression of MBP, MAP2, GAP-43, and SYN were detected in the brain by immunohistochemistry. Motor function was evaluated in the three groups.
RESULTS: In the sham operation group, MBP was abundant in the myelinated nerve fibers. in the electro-acupuncture treatment group, however, the corpus callosum exhibited more MBP staining than the model group. MAP2 expression was increased in the model group, and increased further in the electro-acupuncture treatment group compared with the sham operation group. GAP-43 expression in the cerebral cortex was less in model group than in sham operation, but present in abundance in the electro-acupuncture treatment group. SYN expression in the cerebral cortex was less in the model and electro-acupuncture treatment group compared with the sham operation group. There was no significant difference in SYN expression and distribution between the model and electro-acupuncture treatment groups. Motor function of rats in the electro-acupuncture treatment group was significantly better than the model group (P < 0.05), although function remained lower than the sham operation group (P < 0.05).
CONCLUSION: Two weeks of electro-acupuncture treatment improved motor function in rats, and protein markers related to neural plasticity also changed, which may be a mechanism for improved motor function in rats with ischemic-hypoxic brain injury.