Electroacupuncture pretreatment induces delayed tolerance to focal cerebral ischemia through activation of cannabinoid CB2 receptor in rats
马磊1 侯丽宏1 朱萧玲1 熊利泽1 陈绍洋1
Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University
Objective To investigate the involvement of the CB2 receptor in the neuroprotection conferred by pretreatment with EA in the rat model of focal cerebral ischemia. Methods Experiment 1.Forty-eight male SD rats were randomly assigned to 6 groups(n=8 each). The rats in MCAO group only received MCAO and the rats in EA group received MCAO at 2 hours after the end of EA pretreatment for 30 minutes. The rats in Vehicle +EA group,AM630+EA group,AM251+EA group and AM630+AM251+EA group were intraperitoneally administered with Vehicle,AM630,AM251 respectively and then subjected to MCAO at 2 hours after the end of EA pretreatment. Experiment 2.Forty-eight male SD rats were randomly assigned to 6 groups(n=8 each). The groups and methods are same as experiment 1 except that all the groups except for MCAO group received MCAO at 24 hours after the end of EA pretreatment for 30 minutes. Experiment 3. Forty-five male SD rats were randomly divided into 6 groups: CON (n=9)、EA2h (n=9)、EA6h (n=6)、EA12h (n=6)、EA18h (n=6)、EA24h (n=9) groups. At 2 hours、6 hours、12 hours、18 hours and 24 hours after EA pretreatment, the rats (n=6) from the latter 5 groups were decapitated.The brains removed and cortex and striatum of the right hemispheres were separated for RT-PCR and western blot analysis. The rats from CON、EA2h and EA24h groups (n=3 each) were perfusion-fixed with 4% paraformaldehyde for double immunofluorescence staining. Results Pretreatment with EA reduces infarction volume percentage, improved neurobehavioral score at 72 hours after reperfusion. AM251 and AM630 could respectively reverse the rapid and delayed ischemic tolerance induced by EA pretreatment. Pretreatment with EA up-regulates the CB2 receptor expression in the cortex and striatum of rat brains at 24h after the end of EA stimuli. Conclusion These results suggest that the CB1 and CB2 receptors respectively participated in the rapid and delayed cerebral ischemic tolerance induced by EA pretreatment.
