DL0805抑制血管紧张素Ⅱ通过Ca2+依赖和非Ca2+依赖途径引起的大鼠胸主动脉环收缩

摘要

Objective To investigate the mechanisms of DL0805 , a Rho kinase inhibitor, in the relaxation on the contraction induced by angiotensin Ⅱ (Ang Ⅱ ) in the rat thoracic aorta. Methods Intracellular [ Ca2+ ] ( [ Ca2 +] i) was measured with Fura2/AM in vascular smooth muscle cell(VSMC). Protein level of Rho kinase 1 ( R0CK1 ) , the phosphorylation levels of myosin phosphatase target subunit 1 ( MYPT1) and Akt in the rat aortic rings were detected by Western blotting. Results DL0805 (1 , 10μmol/L) were shown to inhibit both Ang Ⅱ (100 nmol/L)-induced Ca2+ release from internal stores and Ca2+ influx. DL0805 (25、50 μmol/L) significantly attenuated the increased protein level of ROCK1 , the increased phosphorylation levels of MYPT1 and Akt in the aorta stimulated by Ang Ⅱ (100 nmol/L). Conclusions DL0805 inhibits the vasoconstriction induced by Ang Ⅱ in a Ca2+-dependent and Ca2+-independent manner in the rat thoracic aorta.%目的 探讨Rho激酶抑制剂DL0805抑制血管紧张素Ⅱ(angiotensin Ⅱ,Ang Ⅱ)收缩大鼠胸主动脉环的机制.方法 体外培养大鼠胸主动脉平滑肌细胞(vascular smooth muscle cell,VSMC),在有/无1.8 mmol/L Ca2+的环境下采用Fura2/AM荧光探针法测定细胞内游离钙(intracellular calcium,[Ca2+]i)的变化.应用Western blotting检测大鼠胸主动脉环肌球蛋白磷酸酶靶亚基1(myosin phosphatase target subunit 1,MYPT1)和Akt蛋白磷酸化,以及Rho激酶1(Rho kinase 1,ROCK1)蛋白表达水平.结果 DL0805(1、10 μmol/L)抑制Ang Ⅱ(100 nmol/L)引起的VSMC细胞内钙释放和外钙内流.DL0805 (25、50 μmol/L)抑制 Ang Ⅱ(100 nmol/L)引起的MYPT1和Akt磷酸化水平以及ROCK1蛋白表达水平增高.结论 DL0805能抑制Ang Ⅱ通过Ca2+依赖和非Ca2+依赖途径引起的大鼠胸主动脉环收缩.