蛋白激酶SGK-1在高血压性心脏纤维化中的表达及影响

目的:探讨血清和糖皮质激素诱导的蛋白激酶-1(SGK1)在血管紧张素Ⅱ(AngiotensionⅡ,AngⅡ)所诱导高血压性心脏纤维化中的表达及作用。方法:40只雄性C57BL/6小鼠随机分为0.9%氯化钠组和AngⅡ组,每组20只。采用植入式胶囊渗透压泵对小鼠分别灌注0.9%氯化钠和AngⅡ,于第7天时采用鼠尾套法检测小鼠尾动脉血压处死并取其心脏进行组织切片,行HE染色观察心脏组织炎症细胞浸润、Masson染色观察胶原沉积、免疫组织化学染色检测巨噬细胞(Mac-2)及炎症细胞因子[诱导型一氧化氮合酶(iNOS)、白介素1β(IL-1β)、精氨酸酶1(Arg1)]和促纤维化的因子[转化生长因子β(TGF-β)、α平滑肌肌动蛋白(α-SMA)]的表达;Real-time PCR检测SGK1 mRNA表达;Westernblot检测SGK1蛋白水平的表达和活化。结果:与0.9%氯化钠组相比,AngⅡ组灌注7 d时血压显著升高(P<0.01);巨噬细胞Mac2浸润增加、胶原沉积增多、促炎因子(iNOS、IL-1β、Arg1)及促纤维化因子(TGF-β、α-SMA)的表达水平均显著升高(均为P<0.05);Real-time PCR结果显示AngⅡ灌注明显上调SGK1 mRNA表达(P<0.05);Western blot结果显示AngⅡ灌注增加SGK1磷酸化水平(P<0.05)。结论:在高血压性心脏纤维化疾病进程中,炎症反应增加并且SGK1表达明显上调及活性增强,提示SGK1可能是高血压导致心脏纤维化的关键信号分子,并且SGK1可能通过调节炎症反应促进心脏纤维化的进展。

Expression and effect of serum-and glucocorticoid-inducible kinase 1 ( SGK1 ) on the hypertension-induced cardiac fibrosis

Objective:We and others previously have shown that the serum-and glucocorticoid-inducible kinase 1 is a critical molecule for cell proliferation and survival.In this study,we aimed to explore the relationship of SGK1 and hypertension-induced cardiac fibrosis.Methods:40 C57BL/6 mice were infused for 7 days either vehicle(saline,n=20) or a pressor dose of angiotensin II(Ang II,1 500 ng·kg-1·min-1),n=20) with an osmotic mini-pump implanted subcutaneously.Blood pressure was measured by tail-cuff plethysmography method to evaluate the effect of infused Ang II.At day 7,Ang II-or saline-treated mice were euthanized and the hearts were excised and immediately processed for morphological and gene expression analysis.HE staining,immunohistochemistry and Masson staining were used to analyze inflammatory cell infiltration,collagen deposition and cardiac fibrosis.The levels of mRNA and protein of SGK1 were measured by Real-time PCR and Western blot.Results:Compared with normal saline treatment group,blood pressure was significantly increased at 7 days after Ang II treatment(P<0.05).The left ventricular mass index,ejection fraction(EF%) and fractional shortening(FS%) were significantly increased after Ang II infusion(P<0.05).Inflammatory cell infiltration and collagen deposition were significantly increased(P<0.05),while the expression of inflammation cytokines(iNOS,IL-1β,Arg1) and pro-fibrosis cytokines(TGF-β,α-SMA) were significantly increased(P<0.05).The level of mRNA of SGK1 markedly increased one day after Ang II infusion and the level of protein of p-SGK1 significantly increased seven days after Ang II infusion.Conclusion:The expression of SGK1 was markedly increased concomitantly with increased of Inflammatory cell infiltration in mouse hypertensive heart induced by AngⅡ infusion and SGK1 as an important signaling molecular may involve in the process of hypertensive heart disease by regulating inflammatory cells.