多巴胺 D5受体通过抑制氧化应激对扩张型心肌病的调节作用

摘要

目的：探讨多巴胺 D5受体是否会通过抑制氧化应激来影响扩张型心肌病（dilated cardiomyopathy）的发生发展。方法建立心脏特异表达人多巴胺 D5受体突变基因 F173L（α－MHC－hD5F173L）和正常基因（α－MHC－hD5WT）转基因小鼠。用3月龄小鼠，首先检测比较转基因小鼠心脏内 ROS 的产量和 NOX2的表达量。然后对α－MHC－hD5F173L 小鼠通过皮下给 NADPH 氧化酶的抑制剂罗布麻宁（Apocynin）4周，同时给 PBS 作为对照组，然后检测各项心肌病相关指标。同时构建人多巴胺 D5受体突变基因（hD5F173L）和正常多巴胺 D5受体基因（hD5WT）的大鼠心肌细胞（H9C2），检测两者在基础条件下 ROS 产量的变化。结果α－MHC－hD5F173L 转基因小鼠的 NADPH 氧化酶的活性和 NOX2蛋白的表达量均明显高于野生型α－MHC－hD5WT 小鼠，罗布麻宁能显著改善α－MHC－hD5F173L 转基因小鼠的心脏功能。 H9C2－hD5F173L 大鼠细胞系 NOX2的表达量及 ROS 产量高于H9C2－hD5WT 对照细胞。结论多巴胺 D5受体可能通过抑制氧化应激而防止扩张型心肌病的发生发展。%Objective To determine whether dopamine D5 receptor (D5R) regulates the development of dilated cardiomyopathy (DCM) by inhibiting oxidative stress.Methods We developed heart-specific hD5 mutant (α-MHC-hD5F173L) and wild type (α-MHC-hD5WT) transgenic mice.The NOX2 expression and ROS production were tested in the transgenic mice at three month of age.The α-MHC-hD5F173L mice were treated with either NADPH oxidase inhibitor Apocynin (1mmol/kg/day) or phosphate-buffered saline (PBS) as control by intraperitoneal injection for 4 weeks.After then, the indexes of heart function were measured.The hD5WT and hD5F173L were transfected respectively in rat H9C2 cells, in which ROS production and NOX2 expression were detected at basal level.Results The ROS production and NOX2 expression were higher in the heart of α-MHC-hD5F173L than α-MHC-hD5WT mice.Apocynin treatment improved the heart function of α-MHC-hD5F173L mice.NOX2 expression and ROS production were higher in hD5F173L than hD5WT transfected H9C2 cells.Conclusions Dopomine D5 receptor may prevent DCM development by inhibiting oxidative stress.