DADLE对大鼠急性全脑缺血再灌注后海马区神经元ERK信号通路和Caspase-3表达的影响

Effects of δ-opioid Receptor Agonists on Expressions of ERK Signaling Pathway and Caspase-3 Following Cerebral Ischemia-reperfusion in Hippocampus of Rat

目的:观察δ-阿片受体激动剂DADLE([D-Ala2,D-Leu5]enkephali)对大鼠急性全脑缺血再灌注后海马区神经元ERK信号通路和Caspase-3表达的影响。方法:将50只SD大鼠随机分为5组:假手术组(Sham)、模型组(I/R)、DADLE处理组(根据不同剂量可分为2mg/kg[A]、3mg/kg[B]、5mg/kg[C])。采用改良的二血管阻断加低血压法建立全脑缺血再灌注模型。于缺血15min后经颈外静脉注射DADLE并于再灌注120min后处死。开颅取其新鲜海马组织,采用westernblot检测海马组织Caspase-3的表达,以及采用免疫组织化学法检测非磷酸化ERK与磷酸化ERK(P-ERK)的表达状况。结果:Sham组ERK和P-ERK蛋白表达水平显著低于其他各组(P<0.05),DADLE处理组与I/R组相比,其ERK和P-ERK蛋白的表达量明显上调(P<0.05)。海马组织Caspase-3蛋白表达I/R组较Sham组表达明显上调(P<0.05),而DADLE处理组与IR组比较,海马组织Caspase-3蛋白表达明显下降(P<0.05)。结论:DADLE对大鼠急性全脑缺血再灌注后海马区神经元有保护作用,说明DADLE可通过上调ERK信号通路以及抑制Caspase-3的表达而起到保护脑组织的作用。

Objective： To observe the effects of δ -opioid receptor agonist DADLE （ [D-AIa2, D-Leu5]enkephali ） on expression of ERK signaling pathway and Caspase-3 following cerebral ischemia-reperfusion in hippocampus of rat. Method： In total, 50 SD rats were randomly divided into 5 groups： a sham-operated, a I/R and three DADLE-treated （ different drug doses： 2 mg/kg[A], 3 mg/kg[B] and 5 mg/kg[C] ） .Use improvement of two vessels occlusion add hypotension to establish the global cerebral ischemia/reperfusion model in rats.Injecting DADLE through external jugular vein after ischemic 15 min, and the rats were respectively killed after reperfusion 120rain.The expression of Caspase-3 were detected by Western blot, and the expression of non-phosphorylated ERK and phosphorylation of ERK （ P-ERK ） were detected by Immunohistochemistry assay. Result： The expression of ERK and P-ERK was lower in the Sham group than in the others （ P〈0.05 ）, and compared with I/R group, the expression of ERK and P-ERK of each DADLE-treated group was higher obviously （ P〈0.05 ） . The expression of Caspase-3 in hippocampus was higher in the I/R group than in the Sham group, and compared with I/R group, the expression of Caspase-3 of each DADLE-treated group Was lower obviously （ P〈0.05 ） . Conclusion： DADLE may be have some protective effects on neurons in hippocampus after the global cerebral ischemia/reperfusion in rats, and it related. Shows that DADLE can play a role in protecting brain tissue by increasing the expression of ERK signaling pathway and inhibiting the expression of Caspase-3.