Time-dependent effects of electroacupuncture at the Ren channel on extracellular signal-regulated kinases 1/2 expression in focal cerebral ischemia rats

BACKGROUND： The onset of focal cerebral ischemia activates extracellular signal-regulated kinases 1 and 2, regulates cell cycle, promotes cell proliferation and differentiation, and affects the normal stage and function of brain cells. OBJECTIVE： To observe the effects of electroacupuncture at the Ren channel on extracellular signal-regulated kinases 1/2 expression in the lateral cerebral ventricle wall of rats with focal cerebral ischemia. The effects were analyzed at different time points after intervention. DESIGN： Randomized controlled study. SETTING： Department of Anatomy, Sun Yat-Sen University. MATERIALS： A total of 60 healthy adult male Wistar rats weighing （250±10） g were provided by the Experimental Animal Center, Medical College of Sun Yat-Sen University. The animal experiment was conducted with confirmed consent by the local ethics committee. The GB6805-Ⅱ electric acupuncture apparatus was provided by Shanghai Medical Equipment High-techno Company. METHODS： The experiment was performed at the Laboratory of Anatomy, Sun Yat-Sen University, from February to July 2007. All experimental animals were randomly divided into the following groups： normal group （n = 6）, sham operation group （n = 18）, model group （n = 18）, and electroacupuncture group （n = 18）. Middle cerebral artery occlusion （MCAO） was performed in the model group and electroacupuncture group. Zea Longa＇s grading standard was used to assess neurological impairment after reperfusion; animals whose grades were between l and 4 were included in this study. The normal control group was not exposed to MCAO. In sham operation animals, the right common carotid artery （CCA） was isolated, and the external carotid artery （ECA） was damaged, but no embolism was induced. The electroacupuncture group was given acupuncture on the second day after surgery. The acupoint locations were chosen according to Experimental Acupuncture （People＇s Publishing House; 1997; First Edition）. The Chengjiang, Qihai, and Guanyuan acupoints were labeled and connected to a G6805 electroacupuncture apparatus with sparse-dense waves （sparse waves were 30 Hz, dense waves were 100 Hz）, with a frequency of 6-15 V. The duration was 20 minutes. Two days after surgery, the model and sham operation groups were placed with their backs on the operating table, but they received no acupuncture. However, the normal group received acupuncture. The experimental animals under anesthesia were sacrificed on days 7, 14, and 28 post-surgery. Western blot analysis was used to measure expression of extracellular signal-regulated kinases 1/2 in the inferior region of the lateral cerebral ventricle wall. Expression was measured in the normal group at time points corresponding to the sham operation group. MAIN OUTCOME MEASURES： Expression of extracellular signal-regulated kinases 1/2 in the inferior region of the lateral cerebral ventricle wall at different time points after intervention. RESULTS： All 60 rats were included in the final analysis, without any loss. Seven days after MCAO, there was no significant difference in extracellular signal-regulated kinases 1/2 expression in the electroacupuncture group compared to the model group （P 〉 0.05）. However, extracellular signal-regulated kinases 1/2 expression significantly increased in the model group at 14 and 28 days after treatment （P 〈 0.05）. CONCLUSION： Electroacupuncture at the Ren channel can enhance extracellular signal-regulated kinasesl/2 expression in the inferior region of the lateral cerebral ventricle wall of rats with focal cerebral ischemia. However, this effect is not apparent until 14 days after electroacupuncture intervention.