论文部分内容阅读
目的:PKG在血管硝酸甘油(nitroglycerin,NTG)耐受形成中起重要作用,PI3K/Akt信号通路与血管张力调节关系密切,本研究旨在探讨该通路在NTG耐受形成中的作用及其机制。方法:通过猪离体冠状动脉孵育NTG(10~(-5)mol/L,24 h)建立离体NTG耐受模型;通过皮下注射NTG(20 mg/kg体重,每天3次,连续3 d)建立小鼠在体NTG耐受模型;运用离体血管环灌流、Western blot、实时定量PCR及免疫荧光等方法进行研究。结果:离体和在体研究表明,耐受组血管对硝酸甘油的舒张反应较对照组显著减弱,并且耐受组血管的p-Akt(Ser473)蛋白水平显著增加。PI3K的特异阻断剂LY294002与NTG共孵育冠状动脉24 h,可显著抑制耐受组引起的p-Akt(Ser473)蛋白水平升高,同时部分改善了血管对NTG的反应性。耐受组冠状动脉PKG的蛋白和m RNA水平较对照组明显降低,且均可被LY294002所反转。耐受组血管的p-Fox O1(Ser256)蛋白水平较对照组显著升高,且出现由胞核向胞浆的转位,以上现象均可被LY294002所阻断。结论:活化的PI3K/Akt通过促进Fox O1的出核,抑制了PKG的表达,从而导致NTG耐受。
OBJECTIVE: PKG plays an important role in the formation of tolerance to nitroglycerin (NTG), and the PI3K / Akt signaling pathway is closely related to the regulation of vascular tone. The purpose of this study was to investigate the role of this pathway in NTG tolerance and its mechanism . Methods: The in vitro NTG tolerance model was established by incubation of porcine isolated coronary artery with NTG (10 -5 mol / L for 24 h). NTG (20 mg / kg body weight, 3 times a day for 3 days ) To establish mouse in vivo NTG tolerance model; using in vitro vascular perfusion, Western blot, real-time quantitative PCR and immunofluorescence and other methods were studied. RESULTS: In vitro and in vivo studies showed that the vasodilatory responses to nitroglycerin in the tolerated group were significantly weaker than those in the control group, and the p-Akt (Ser473) protein levels in the tolerated group were significantly increased. PI3K-specific blocker LY294002 co-incubated with NTG for 24 h in the coronary arteries, which significantly inhibited the increase of p-Akt (Ser473) protein level in the tolerated group and partly improved the vascular reactivity to NTG. PKG protein and m RNA levels in the tolerated coronary arteries were significantly lower than those in the control group, and both were reversed by LY294002. The protein level of p-FoxO1 (Ser256) in the tolerant group was significantly higher than that in the control group, and translocated from the nucleus to the cytoplasm. These phenomena could be blocked by LY294002. Conclusion: Activated PI3K / Akt can inhibit the expression of PKG by promoting the nuclear export of Fox O1, leading to NTG tolerance.