摘要
目的利用特异表达人多巴胺D5突变基因F173L(D5F173L)的转基因小鼠,探讨多巴胺D5受体在高血压发生中的作用机制。方法采用鼠尾无创法测量野生型与D5F173L小鼠血压。使用代谢笼收集小鼠24h尿量并用电极法测定尿钠、尿钾水平。用哇巴因法检测小鼠近曲小管上皮细胞(mRPT)转染野生型、D5F173L质粒后Na+-K+-ATP酶活性。利用DHE试剂盒检测小鼠肾脏中超氧阴离子含量,观察氧化应激水平的变化。通过荧光定量PCR筛选出与氧化应激相关基因mRNA表达水平的变化。结果 D5F173L转基因小鼠收缩压、平均动脉压、肾脏尿钾、氧化应激水平、过氧化物酶体增殖物激活受体(PPAR)γmRNA的表达高于野生型小鼠[收缩压(121±5)比(98±4)mm Hg、平均动脉压(85±3)比(76±5)mm Hg,尿钾(0.60±0.09)比(0.46±0.05)mmol/d,氧化应激的荧光密度:0.076±0.006比0.051±0.009,PPARγmRNA:0.89±0.33比0.48±0.39,均P<0.05],24h尿量、尿钠、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶1(GPX-1)、过氧化氢酶(CAT)mRNA的表达低于野生型小鼠[尿量(1.57±0.17)比(2.01±0.10)mL/d、尿钠(0.36±0.02)比(0.46±0.05)mmol/d,SOD mRNA 1.28±0.33比0.79±0.39、GPX-1mRNA 1.09±0.11比0.75±0.20、CAT mRNA 1.42±0.34比0.93±0.48,均P<0.05]。转染D5F173L质粒的近曲小管上皮细胞Na+-K+-ATP酶活性较野生型和空白对照组升高[(136.9±42.3)%比(88.6±23.9)%,(99.7±22.1)%,均P<0.05]。结论氧化应激水平通过增加肾脏Na+-K+-ATP酶活性使肾脏利尿排钠功能受损,可能是D5F173L转基因小鼠血压升高的原因之一。
Objective To investigate the mechanism of dopamine D5 receptor involved in hypertension using D5F173L transgenic mice that specificly express human D5F173L mutant gene. Methods The blood pressures （BP） in wild-type （WT） and D5F173L transgenic mice were measured by the tailcuff method. 24-hour urine sam- ples were collected in metabolic cages, the concentration of urine sodium and potassium were determined by electrode method. The reactive oxygen species （ROS） production of kidney were detected by dihydroethidium （DHE Beyo- time）. The mRNA expression levels of several oxidative stress-related genes were quantified by real-time PCR. Ouabain assay was used to determine the activity of Na＋-K＋-ATPase in mRPT cells. Results The systolic and mean artery blood pressure of D5 F173L transgenic mice were significantly higher than that of the WT mice [systolic blood pressure： （121±5） vs （98±4）mm Hg; mean artery blood pressure： （85±3）vs（76±5）mm Hg; P〈0.05]. 24-hour urine volume and urinary Na＋ excretion in D5F173L transgenic mice were significantly lower than that in WT mice [（1.57±0. 17） vs （2.01±0.10）mL/d; （0.36±0.02） vs （0.46±0.05）mmol/d, P〈0.05]. The urine potassium was significantly higher in D5 F173L transgenic mice than in WT mice [ （ 0. 60 ±0. 09 } vs （ 0. 46 ± 0. 05 ） mmol/d, P〈0.05]. Compared to WT mice, the level of ROS was significantly higher in D5F173L transgenic mice [the mean flourscence indensity of kidney： 0. 076±0. 006 vs 0. 051±0. 009, peroxisome proliferator-activated receptor（PPAR）γ mRNA：0. 89±0. 33 vs 0.48±0.39, P〈0.05]. Moreover, the mRNA expression of SOD 1.28±0.33 vs 0.79±0, 39, GPX-1 1.09±0.11 vs 0.75±0.20 and CAT 1.42±0.34 vs 0. 93 ± 0. 48 , were significantly de- creased Whereas the mRNA expression of PPAR7 was significantly increased in D5F173L transgenic mice. The ac- tivity of Na＋-K＋-ATPase was significantly increased in the mRPT cells transfected with D5 F173L plasmid than the control and WT plasmid transfected group [（136.9±42.3）% vs （88.6±23.9）% vs （99.7±22.1）%, P〈0.05）. Conclusion The increased oxidative stress maybe an answer to the elevated blood pressure of D5F173L transgenic mice through the change of Na＋ K＋-ATPase activity and urinary sodium excretion in kidney.
出处
《中华高血压杂志》
CAS
CSCD
北大核心
2014年第5期468-474,共7页
Chinese Journal of Hypertension
基金
国家自然科学基金青年基金(81100500、81070559、31130029)
