腺苷A1受体参与单次电针预处理诱导的脑急性缺血耐受

Effect of adenosine A1 receptor in the rapid ischemic tolerance induced by pretreatment with single electroacupuncture in rats

目的 :探讨腺苷 A1受体是否参与单次电针预处理诱导的脑急性缺血耐受。方法 :4 0只健康雄性SD大鼠 (2 80～ 32 0 g)随机分为对照组 (C)、8环戊基 1,3二丙基黄嘌呤 (DPCPX)缺血组 (DI)、电针组(EA)、二甲基亚砜 (DMSO)电针组 (DME)和 DPCPX 电针组 (DPE) 5组 (n=8) :C组给予大脑中动脉栓塞(MCAO)前 3h腹腔注射质量分数为 1%的戊巴比妥钠 4 0 mg/ kg和生理盐水 1ml/ kg,DI组给予 1%戊巴比妥钠 4 0 m g/ kg和质量分数为 0 .1%的 DPCPX1m g/ kg;EA组、DME组和 DPE组分别于电针刺激百会穴前30 min腹腔注射生理盐水 1ml/ kg、DMSO 1m l/ kg和 0 .1%的 DPCPX 1mg/ kg,3组均在腹腔注射 1%戊巴比妥钠 4 0 mg/ kg麻醉下电针刺激百会穴 30 min后 2 h给予局灶性脑缺血。采用颈内动脉尼龙线线栓法致大脑中动脉栓塞 (12 0 m in)模型 ,观察再灌注后 2 4 h时神经功能缺损评分 ,并取大脑行 2 ,3,5氯化三苯四唑 (TTC)染色以测量脑梗死容积。结果 :术后动物均存活。EA组和 DME组再灌注 2 4 h时神经功能缺损评分明显低于对照组 (P<0 .0 1和 P<0 .0 5 ) ,脑梗死容积也都明显小于对照组 (P均 <0 .0 5 ) ;而 DI组和 DPE组与对照组比较神经功能缺损评分和脑梗死容积均无显著性差异。结论 :单次电针刺激百会穴诱导大脑急性缺血耐?

Objective: To investigate whether adenosine is involved in the rapid tolerance induced by pretreatment with single electroacupuncture in rats. Methods: Forty male SD rats (280-320 g) were assigned into five groups(n=8 in each group): control group, 8-cyclopentyl-1,3-dipropylxanthine (DPCPX)- ischemic(DI) group, electroacupuncture-pretreated (EA) group, dimethy 1 sulfoxide(DMSO, solvent of DPCPX) plus electroacupuncture-pretreated group(DME), and DPCPX plus electroacupuncture-pretreated(DPE) group. The rats were injected with 40 mg/kg pentobarbital sodium plus 1 ml/kg saline and 40 mg/kg pentobarbital sodium plus 1 mg/kg DPCPX 3 hours before middle cerebral artery occlusion(MCAO) in control and DI group respectively. The animals were injected with 1 ml/kg saline, 1 ml/kg DMSO and 1 mg/kg DPCPX 30 minutes before pretreatment with electroacupuncture at the Baihui acupoint(百会穴). The animals were treated with electroacupuncture at Baihui acupoint under anesthesia with 40 mg/kg pentobarbital sodium in EA, DME and DPE group respectively. The middle cerebral artery was occluded with 3-0 nylon monofilament 120 minutes after pretreatments, the changes of neurological deficit scores(NDS) was evaluated at 24 hours after reperfusion. The infarct volume was then assessed with 2% 2,3,5-triphenyltetrazolium chloride(TTC) staining after the neurological outcome evaluation. Results: All animals survived. The NDS in EA and DME groups were lower than those in controls (P<0.01 and P<0.05 respectively), and the infarct volume in EA and DME groups were significantly smaller than that in controls at 24 hours after reperfusion( all P<0.05). There was no difference among DI, DPE and controls. DPCPX partially reversed the amelioration of NDS and the reduction of infarct volume that was induced by pretreatment with single electroacupuncture after focal ischemia, whereas the agent itself did not affect the NDS and volume after ischemia. Conclusion: The present study indicates that pretreatment with single electroacupuncture induces acute ischemic tolerance possibly via a partial mediation of the central adenosine receptors in the brain.