CAJ | 학술논문

目的探讨过氧化氢(H2O2)对胆总管结扎诱导的肝硬化门静脉高压症(PHT)大鼠肠系膜动脉收缩反应性的影响及其在RhoA/Rho激酶(ROCK)信号通路中的作用机制.方法结扎胆总管建立肝硬化门静脉高压症大鼠模型.每日1次腹腔内注射生理盐水或聚乙二醇-过氧化氢酶(PEG-catalase,10 000 U/kg)共8d,相应处理正常大鼠.测定肠系膜动脉H2O2含量,利用血管灌流系统测定肠系膜微动脉对去甲肾上腺素的反应.检测大鼠肠系膜动脉α1肾上腺素能受体和β-arrestin2蛋白表达及其相互作用的变化,以及肠系膜动脉内ROCK-1蛋白量和活性的变化.结果肝硬化PHT大鼠的离体肠系膜微动脉对去甲肾上腺素剂量反应曲线右移,EC50升高,PEG-catalase降低动脉过氧化氢含量后能逆转上述表现.各组肠系膜动脉的α1肾上腺素能受体含量不变.但是,PEG-cat-alase处理后肝硬化PHT大鼠肠系膜动脉内β-arrestin-2蛋白量降低,与α1肾上腺素能受体结合程度也降低;PHT大鼠肠系膜动脉内ROCK-1蛋白含量及其活性明显升高.结论肝硬化PHT肠系膜动脉H2O2含量升高,引起抑制蛋白β-arrestin-2水平上升,与α1肾上腺素能受体结合能力增强,使得ROCK蛋白含量和活性均明显下降,造成肠系膜动脉对缩血管物质的收缩低反应性.
목적 탐토과양화경(H2O2)대담총관결찰유도적간경화문정맥고압증(PHT)대서장계막동맥수축반응성적영향급기재RhoA/Rho격매(ROCK)신호통로중적작용궤제.방법 결찰담총관건립간경화문정맥고압증대서모형.매일1차복강내주사생리염수혹취을이순-과양화경매(PEG-catalase,10 000 U/kg)공8d,상응처리정상대서.측정장계막동맥H2O2함량,이용혈관관류계통측정장계막미동맥대거갑신상선소적반응.검측대서장계막동맥α1신상선소능수체화β-arrestin2단백표체급기상호작용적변화,이급장계막동맥내ROCK-1단백량화활성적변화.결과 간경화PHT대서적리체장계막미동맥대거갑신상선소제량반응곡선우이,EC50승고,PEG-catalase강저동맥과양화경함량후능역전상술표현.각조장계막동맥적α1신상선소능수체함량불변.단시,PEG-cat-alase처리후간경화PHT대서장계막동맥내β-arrestin-2단백량강저,여α1신상선소능수체결합정도야강저;PHT대서장계막동맥내ROCK-1단백함량급기활성명현승고.결론 간경화PHT장계막동맥H2O2함량승고,인기억제단백β-arrestin-2수평상승,여α1신상선소능수체결합능력증강,사득ROCK단백함량화활성균명현하강,조성장계막동맥대축혈관물질적수축저반응성.
Objective To explore the role of hydrogen peroxide in mesenteric artery contraction of cirrhotic rats with portal hypertension,which was induced by bile duct ligation.Possible mechanism in RhoA/ROCK signal pathway was also part of the focus.Methods The bile duct ligation-induced cirrhotic rats and normal rats (control group) were treated equally with PEG-catalase(10 000 U/kg-1 · d-1,ip.) or by its vehicle for 8 days.Then the level of H2O2 in mesenteric arteries was detected.The contractile response to norepinephrine of arterioles was analyzed by vascular perfusion system.The protein expressions of the α1 adrenergic receptor,β-arrestin-2 and Rho kinase-1 (ROCK-1),and the activity of ROCK-1 were measured by western blot.In addition,the interaction of α1-adrenergic receptor with β-arrestin-2 was assessed by co-immunoprecipitation.Results Compared to normal rats,the dose-response curve of the mesenteric arterioles in response to norepinephrine shifted to the right,and the EC 50 increased in the rats with portal hypertension.PEG-catalase treatment can decrease the hydrogen peroxide level in arteries,thus significantly lowered EC50 and improved the reactivity to norepinephrine of the mesenteric arterioles in portal hypertension rats.No significant difference in the α1-adrenergic receptor amounts was observed among groups.There was remarkable decreases in the protein expressions of β-arrestin-2 and its interaction with the α1-adrenergic receptor in cirrhotic rats with PEG-catalase treatment.PEG-catalase also increased the amount and activity of ROCK-1 in cirrhotic rats.Conclusions The level of hydrogen peroxide increases in the mesenteric arteries in bile duct ligation-induced cirrhotic rats.And it enhances the β-arrestin-2 expression and its interaction with the α1-adrenergic receptor,which subsequently decreases the amount and activity of ROCK as well as the contractility of mesenteric arteries in response to vasoconstrictors.