Objective: To compare the effect of electroacupuncture (EA) of "Neiguan" (PC6) of the Pericardium Meridian, "Shenmen" (HT7) of the Heart Meridian，"Shuigou" (GV26) of the Governor Vessel and "Zhaohai" (KI6) of the Kidney Meridian on myocardial and cerebral cell apoptosis in cerebral ischemia (CI) rats, so as to explore its mechanism underlying improvement of CI based on the theory of "Heart-brain Correlation".
Methods: Forty-eight SD rats (half male and half female) were randomly divided into normal control, model, PC6, HT7, GV26 and KI6 groups (n＝8 in each one). The CI model was established by occlusion of the middle cerebral artery (MCAO). EA (4 Hz/20 Hz, 1.5 mA) was applied to the right PC6, HT7, GV26 or KI6 respectively for 30 min, once every 12 h for 5 times. The cell apoptosis of the ischemic myocardial and cerebral tissues was detected by TUNEL method, and the expression of cerebral and myocardial Bax and Bcl-2 was determined by using immunohistochemistry.
Results: Following modeling, the cell apoptosis percentages and Bax-positive cells of both myocardial and cerebral tissues were significantly increased in the model group in comparison with the control group (P<0.01). After EA intervention, the cerebral apoptotic percentage and cerebral Bax-positive cells in the cerebral tissue of the PC6, HT7 and GV26 groups, and the myocardial apoptosis percentage in the PC6 and HT7 groups, as well as the myocardial Bax-positive cells in the PC6 group were obviously decreased (P<0.05, P<0.01), while the cerebral Bcl-2 positive cells in the PC6, HT7 and GV26 groups, and the myocardial Bcl-2 positive cells in the PC6 and HT7 groups were significantly increased relevant to the model group (P<0.01, P<0.05). No significant changes were found in the KI 6 group in the cell apoptosis index and percentages and Bax- and Bcl-2-positive cells of both myocardium and cerebral cortex tissues compared with the model group (P>0.05)．.
Conclusion: EA stimulation of PC6 and HT7 can inhibit CI injury induced cell apoptosis of cerebral and myocardial tissues in CI rats, which is possibly associated with its effects in down-regulating Bax expression and up-regulating Bcl-2 expression of both myocardial and cerebral tissues.
Keywords: Bax; Bcl-2; Cerebral ischemia; Electroacupuncture; Heart-brain correlation; Myocardial/cerebral cell apoptosis; Neiguan (PC6); Shenmen (HT7).