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BACKGROUND: Studies have shown that electro-acupuncture at the Ren meridian could improve proliferation of subventricular zone neural stem cells in cerebral-ischemic rats. However, there are few reports on the influence of electro-acupuncture at the Du meridian on neural stem cell proliferation.OBJECTIVE: To observe the influence of electro-acupuncture at Ren and Du meridians on neural stem cell proliferation in the subventricular zone and altered signal transduction in cerebral ischemia rats.DESIGN, TIME AND SETTING: A randomized, controlled, animal experiment was performed at the Laboratory of Human Anatomy, Medical College of Sun Yat-sen University from May 2006 to February 2008.MATERIALS: Mouse anti-rat bromodeoxyuridine (BrdU) monoclonal antibody was provided by Sigma, USA; mouse anti-rat nestin monoclonal antibody and extracellular signal-regulated protein kinase (ERK) specific inhibitor PD98059 were provided by Calbiochem, Germany; acupuncture needle was provided by Suzhou Acupuncture Supplies, China.METHODS: A total of 126 rats were randomly assigned to four groups: model (n = 36), Du meridian (n = 36), Ren/Du meridian (n = 36), and Ren/Du meridian + PD98059 (n = 18). Rats in the Ren /Du meridian + PD98059 group were observed on days 7 (n = 6) and 14 (n = 12) after cerebral ischemia injury. Rats in the model, Du meridian, and Ren/Du meridian groups were observed on days 7, 14, and 28 after cerebral ischemia injury, with 12 rats per group at each time point. Thread occlusion was used to establish middle cerebral artery occlusion models. Electro-acupuncture was performed at Renzhong (DU 26) and Baihui (DU 20) acupoints in the Du meridian group, as well as Chengjiang (RN 24), Guanyuan (RN 4), Renzhong, and Baihui acupoints in the Ren/Du meridian and Ren/Du meridian + PD98059 groups 2 days after model establishment. In addition, electro-acupuncture stimulation with disperse-dense waves was performed, with 30 Hz disperse wave, 100 Hz dense wave, and 5 V intensity for 20 minutes. Rats in the Ren/Du meridian + PD98059 group were treated with 0.2 μg PD98059 injection into the subventricular zone, 2 μL per rat. Rats in the model group were not treated with electro-acupuncture. MAIN OUTCOME MEASURES: BrdU/nestin immunofluorescent staining was used to detect proliferating neural stem cells in the subventricular zone of cerebral ischemia rats; West blot was used to determine phosphorylated ERK1 and 2 (pERK1/2) expression in the subventricular zone.RESULTS: On days 14 and 28 after cerebral ischemia, there were significantly more BrdU-positive and BrdU/nestin-positive cells in the Ren /Du meridian group compared with the Du meridian group (P < 0.05). PD98059 decreased the number of BrdU-positive and BrdU/nestin-positive cells induced by electro-acupuncture at the Ren and Du meridians (P < 0.05). On days 7, 14, and 28 after treatment, pERK1/2 expression was significantly greater in the Du meridian and Ren/Du meridian groups compared with the model group (P < 0.05). The promoting effect of electro-acupuncture at Ren and Du meridians on ERK1/2 phosphorylation was superior to electro-acupuncture at the Du meridian alone on day 14 after model induction (P < 0.05). However, PD98059 completely abolished the promoting effect of electro-acupuncture at Ren/Du meridians on pERK1/2 expression (P < 0.05).CONCLUSION: Electro-acupuncture at Ren and Du meridians increased proliferation of subventricular zone neural stem cells, which was related to activation of the ERK pathway in a rat model of cerebral ischemia injury.