mmLDL对小鼠肠系膜动脉α_1受体介导的血管收缩及相关蛋白表达影响的研究

Study of α_1 adrenoceptor-mediated vasoconstriction and protein expressions induced by mm LDL in mouse mesenteric artery

目的探讨mm LDL对小鼠肠系膜动脉α1受体的作用。方法小鼠尾静脉注射mm LDL,微血管肌张力描记仪观察NA引起的小鼠肠系膜动脉收缩量效曲线变化,RTPCR、Western blot检测α1受体及α2受体表达。结果mm LDL引起NA收缩量效曲线明显增强,表现为Emax值由生理盐水(NS)组的(120.75±3.44)%上升为(161.00±6.87)%(P<0.01),p EC50值由NS组的(5.65±0.05)上升为(6.20±0.08)(P<0.01)。α1受体拮抗剂哌唑嗪引起量效曲线的明显右移,mm LDL引起α1受体m RNA水平、蛋白表达明显增加,对α2受体表达基本没有影响。结论尾静脉注射mm LDL上调小鼠肠系膜动脉α1受体。

Aim To investigate the effects of mmLDL on the up-regulation ofα1 receptors in moues mesenteric arteries. Methods Mice tail intravenous injection of mmLDL was used . Vitro sensitive myograph was employed to examine Noradrenaline （ NA） induced vascular contraction on mice mesenteric artery, and the mRNA and protein expressions ofα1 andα2 receptors were an-alyzed by real-time PCR and Western blot, respective-ly. Results mmLDL significantly increased NA in-duced concentration-contractile curve, and the data of Emax and pEC50 were from （ 122. 61 ± 9. 40 ）% and （5. 65 ± 0. 05 ） in normal saline （ NS ） group to （161. 01 ± 6. 90 ）% and （ 6. 20 ± 0. 08 ） in mmLDL group （P 〈0. 01, P 〈0. 01）, respectively. The α1 adrenoceptor antagonist prazosin shifted the concentration-contractile curve induced by NA towards right. Af-ter using mmLDL, the mRNA and protein levels of α1 adrenoceptor were significantly increased, but the mR-NA and protein levels of α2 adrenoceptor were not changed. Conclusion Tail intravenous injection of mmLDL enhances the vascular expressions of α1 adre-noceptors and the contractile effects mediated byα1 ad-renoceptors.