TIPE2在小鼠脓毒症心肌损伤中的作用:与AKT/GSK-3β/β-catenin信号通路的关系

Role of TIPE2 in sepsis-induced myocardial injury in mice:the relationship with AKT/GSK-3β/β-catenin signaling pathway

目的评价肿瘤坏死因子α诱导蛋白家族8样蛋白2(TIPE2)在小鼠脓毒症心肌损伤中的作用及其与丝氨酸苏氨酸蛋白激酶(AKT)/糖原合酶激酶3β(GSK-3β)/β-连环蛋白(β-catenin)信号通路的关系。方法选择16只雄性野生型C57BL/6N小鼠和16只雄性TIPE2基因敲除C57BL/6N小鼠,6~8周龄,体质量20~25 g,按照随机数字表法分为野生型假手术组(WT-Sham组)、野生型CLP组(WT-CLP组)、TIPE2基因敲除型假手术组(WT-Sham组)和TIPE2基因敲除CLP组(KO-CLP组),每组8只。采用盲肠结扎穿孔法制备脓毒症小鼠急性心肌损伤模型。术后24 h时采集下腔静脉血标本,采用ELISA法检测血清心肌cTnI浓度,然后处死小鼠,取心肌组织,HE染色观察病理学结果,采用q-PCR法检测TNF-α、IL-1β及IL-6的mRNA表达,Western blot法检测TIPE2、磷酸化AKT(p-AKT)、磷酸化(p-GSK-3β)及β-catenin表达。结果与相应Sham组比较,相应CLP组血清cTnI浓度升高,心肌组织TNF-α、IL-1β、IL-6的mRNA表达、p-AKT、p-GSK-3β和β-catenin表达上调,TIPE2表达下调(P<0.05),发生心肌病理学损伤;与WT-CLP组比较,KO-CLP组血清cTnI浓度升高,心肌组织TNF-α、IL-1β、IL-6的mRNA表达、p-AKT、p-GSK-3β和β-catenin表达上调,TIPE2表达下调(P<0.05),心肌病理学损伤加重。结论TIPE2可能通过抑制AKT/GSK-3β/β-catenin信号通路减轻脓毒症小鼠心肌损伤。

Objective To evaluate the role of tumor necrosis factor-alpha-induced protein-8 like-2(TIPE2)in sepsis-induced myocardial injury and the relationship with serine-threonine kinase(AKT)/glycogen synthase kinase-3β(GSK-3β)/β-catenin signaling pathway in mice.Methods Sixteen male wild-type C57BL/6N mice and 16 TIPE2-gene knockout C57BL/6N mice,aged 6-8 weeks,with a body mass index of 20-25 g,were divided into 4 groups using a random number table method:wild-type+sham operation group(group WT-sham),wild-type+cecal ligation and perforation(CLP)group(group WT-CLP),TIPE2-gene knockout sham operation group(group KO-sham)and TIPE2-gene knockout CLP group(group KO-CLP),with 8 mice in each group.The model of myocardial injury induced by sepsis was developed by CLP in anesthetized animals.Blood samples from the inferior vena cava were collected at 24 h after surgery for determination of the concentrations of cardiac troponin I(cTnI)in serum by enzyme-linked immunosorbent assay.Then the mice were sacrificed and myocardial tissues were collected for determination of the pathological changes(by hematoxylin and eosin staining),expression of tumor necrosis factor-alpha(TNF-α),interleukin-1 beta(IL-1β)and IL-6 mRNA(by quantitative polymerase chain reaction),and expression of TIPE2,phosphorylated AKT(p-AKT),phosphorylated GSK-3β(p-GSK-3β)andβ-catenin(by Western blot).Results Compared with the corresponding Sham groups,the serum cTnI concentration was significantly increased,the expression of TNF-α,IL-1βand IL-6 mRNA and expression of p-AKT,p-GSK-3βandβ-catenin in myocardial tissues were up-regulated,the expression of TIPE2 was down-regulated(P<0.05),and the pathological changes of myocardium were found in corresponding CLP groups.Compared with group WT-CLP,the serum cTnI concentration was significantly increased,the expression of TNF-α,IL-1βand IL-6 mRNA and expression of p-AKT,p-GSK-3βandβ-catenin in myocardial tissues were up-regulated,the expression of TIPE2 was down-regulated(P<0.05),and the pathological changes of myocardium were aggravated in group KO-CLP(P<0.05).Conclusions TIPE2 reduces the myocardial injury probably through inhibiting the AKT/GSK-3β/β-catenin signaling pathway in septic mice.