OBJECTIVE: To investigate the difference of protective effect of electroacupuncture (EA) at different times pretreating myocardial ischemia-reperfusion injury (MIRI) and the protein expressions of ULK1 and Beclin-1 in myocardial tissue, so as to explore the relation of the difference and autophagic mechanism. METHODS: Sixty-three male SD rats were randomized into 7 groups, a sham group, a model group, an EA pretreating for 1 d (EA-1d) group, an EA pretreating for 2 d (EA-2d) group, an EA pretreating for 3 d (EA-3d) group, an EA pretreating for 4 d (EA-4d) group, an EA pretreating for 5 d (EA-5d) group, 9 rats in each group. All the rats in the pretreating groups were treated with EA 1-5 days before MIRI surgery. EA (2 Hz/100 Hz, 2 mA) was used at bilateral "Neiguan (PC 6)" for 20 min. All the rats except for those in the sham group was underwent left thoracotomy and ligation of the left anterior descending (LAD) coronary artery for 30 minutes followed by 4 hours of reperfusion to establish the MIRI model. The same operation was performed in the sham group except for the ligation of the LAD. Throughout the experiment, electrocardiogram was continuously monitored. The myocardial infarct sizes were assessed by Evans blue and triphenyltetrazolium chloride (TTC) staining. The serum concentrations of cardiac troponinⅠ(cTnⅠ) was detected by ELISA. The expressions of ULK1 and Beclin-1 in the heart tissues were analyze by Western blot. RESULTS: Compared with the sham group, the concentrations of cTnⅠ and the protein expressions of ULK1 and Beclin-1 increased in the model group (all <0.05). Compared with the model group, the infarct sizes decreased in the EA-1d, EA-2d, EA-3d, EA-4d and EA-5d groups (all <0.05), with less risk sizes in the EA-3d, EA-4d and EA-5d groups (all <0.05). The levels of cTnⅠin the EA-4d and EA-5d groups decreased ( both <0.05); the expressions of ULK1 protein decreased in the EA-1d, EA-2d, EA-3d, EA-4d and EA-5d groups (all <0.05); the expressions of Beclin-1 protein decreased in the EA-2d, EA-3d, EA-4d and EA-5d groups (all <0.05). The infarct sizes in the EA-4d and EA-5d groups were lower than that in the EA-1d group (both 0.05). The cTnⅠconcentration in the EA-4d group was less than that in the EA-1d group (<0.05). CONCLUSION Pretreatment with EA for 1-5 days can improve the infarct size in MIRI, with better effect of the pretreatment for 4-5 days. The cardioprotective effect may be related to the inhibition of autophagy. But the difference of the protective effects is not related to the protein expressions of ULK1 and Beclin-1.
Acupuncture Points ; Animals ; Autophagy ; Electroacupuncture ; Male ; Myocardial Ischemia ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To compare the effects of electroacupuncture (EA) at different time during reperfusion on the expression of autophagy-related protein Bcl-2 and Beclin1 in myocardial tissue in rats with myocardial ischemia reperfusion injury (MIRI), and to explore the autophagy-related mechanism of EA on protecting MIRI. METHODS: A total of 72 SD rats were randomly divided into a sham operation group, a model group, a RA group, a RB group, a RC group and a RD group, 12 rats in each group. Except the sham operation group, the rats in the remaining groups were treated with ligating the left anterior descending artery (LAD) for 30 minutes followed by reperfusion to establish the model of MIRI. The rats in the sham operation group were treated with crossing a line through the LAD. The rats in the model group did not receive treatment. The rats in the RA group, RB group, RC group and RD group were treated with EA at "Neiguan" (PC 6) for 20 min, starting at 0 h, 0.5 h, 1 h, 2 h after reperfusion. Evans Blue-TTC double-staining was employed to evaluate myocardial infarct size; the serum CK-MB was detected by ELISA and the expression of Bcl-2 and Beclin1 protein in myocardial tissue were detected by Western blot. RESULTS: Compared with the model group, the percentage of myocardial infarct size in the RB group, RC group and RD group was decreased significantly (all <0.05), and the reduction in the RB group was more significant than that in the RC group and RD group (both <0.05). Compared with the sham operation group, the expression of CK-MB and Beclin1 in the model group was significantly increased, but the expression of Bcl-2 was significantly decreased (all <0.01). Compared with the model group, the expression of CK-MB and Beclin1 was decreased significantly in RA group, RB group, RC group and RD group (all <0.05), but the expression of Bcl-2 was significantly increased (all <0.05). Compared with the RA group, the expression of CK-MB was decreased in the RB group and RC group (both <0.05) but the expression of Bcl-2 was increased (both <0.01); the expression was not significantly different from that in the RD group (>0.05); the increasing of Bcl-2 in the RB group was more significant than that in RC group (<0.05). The expression of Beclin 1 in the RB group was significantly lower than that in the RA group (<0.05), but there was no significant difference among other EA groups (all >0.05). CONCLUSION EA at different time during reperfusion could reduce myocardial infarct size in rats with MIRI, and EA at 0.5 h after reperfusion has best efficacy; this protective effect may be achieved by increasing Bcl-2 expression and reducing Beclin1 expression to inhibit overautophagy during reperfusion.
Animals ; Beclin-1 ; Electroacupuncture ; Humans ; Myocardial Ischemia ; Myocardial Reperfusion Injury ; Myocardium ; Rats ; Rats, Sprague-Dawley