TAK-242通过调控JAK2/STAT3通路抑制小鼠心肌缺血再灌注损伤炎症反应

目的：探讨Toll样受体4拮抗剂TAK-242抑制小鼠心肌缺血/再灌注损伤（ischemia/reperfusion，I/R）炎症反应的分子机制。方法：选用48只雄性C57BL/6小鼠随机分为4组：假手术组（sham）、模型组（I_30min /R_24h）、给药组[I/R+TAK-242（3 mg·kg^-1）]、干预组[I/R+TAK-242+AG490（15 mg·kg^-1）]。再灌注24 h后心脏超声检测小鼠心功能，氯化三苯基四氮唑（TTC）染色法测定心肌梗死面积，HE染色观察心肌病理改变，WB检测心肌JAK2/STAT3磷酸化水平，ELISA检测血清IL-6、TNF-α、IL-10和高迁移率族蛋白B1（HMGB1）浓度。结果：与sham组比较，I/R组小鼠左心室收缩期直径（LVIDs）延长（P<0.01），左心室射血分数（LVEF）和左心室短轴缩短分数（LVFS）显著降低（P<0.001或P<0.01），心梗面积明显增加并出现心肌炎性浸润，心肌p-JAK2/p-STAT3表达明显升高（P<0.01或P<0.05），血清IL-6、IL-10、TNF-α和HMGB1水平显著升高（P<0.001或P<0.01）。与I/R组比较，TAK-242给药组小鼠LVIDs缩短（P<0.05），LVEF和LVFS显著升高（P<0.01或P<0.05），心梗面积缩小（P<0.01），心肌炎症浸润减轻，心肌p-JAK2/p-STAT3表达降低（P<0.01或P<0.05），血清IL-6和TNF-α水平明显下降（P<0.001或P<0.01），而IL-10和HMGB1浓度进一步升高（P<0.01）。与TAK-242给药组比较，AG490干预可显著加强TAK-242治疗作用，包括心肌收缩功能增强，心梗面积缩小及炎性浸润程度减轻，心肌p-JAK2/p-STAT3表达降低（P<0.05），血清IL-6、TNF-α浓度下降而IL-10、HMGB1浓度升高（P<0.01或P<0.05）。结论： Toll样受体4拮抗剂TAK-242抑制小鼠I/R炎症反应与JAK2/STAT3信号通路失活有关。

Anti-inflammatory effect of TAK-242 against myocardial ischemia/reperfusion injury in mice via regulating JAK2/STAT3 signaling pathway

OBJECTIVE To investigate the anti-inflammatory mechanism of an antagonist for Toll-like receptor 4, TAK-242, against myocardial ischemia/reperfusion injury (I/R) in C57BL/6 mice.METHODS Male C57BL/6 mice (n=48) were randomized into four groups:sham, I_30min/R_24h,[I/R+TAK-242 (3 mg·kg^-1)] and[I/R+TAK-242+AG490(15 mg·kg^-1)]. At 24h after reperfusion, cardiac function, myocardial infarct size and myocardial pathological pattern of mice were evaluated with echocardiography, triphenyltetrazolium chloride (TTC) and HE staining, respectively. Additionally, the protein level of p-JAK2/p-STAT3 was determined by Western blot, and the serum levels of IL-6, TNF-α, IL-10 and HMGB1 were detected by ELISA.RESULTS In I/R mice, left ventricular systolic diameter (LVIDs) was shortened (P<0.01), left ventricular ejection fraction (LVEF) and left ventricular short axis shortening fraction (LVFS) were both decreased significantly (P<0.001 or P<0.01), myocardial infarction size was large, myocardial inflammatory cell infiltration was severe, the expression of p-JAK2/p-STAT3 was increased (P<0.01 or P<0.05), and the serum concentrations of IL-6, TNF-α, IL-10 and HMGB1 were significantly increased (P<0.001 or P<0.01) compared with the sham group. TAK-242 significantly extended LVIDs (P<0.05), increased LVEF and LVFS (P<0.01 or P<0.05), reduced myocardial infarction and improved myocardial inflammatory cell infiltration, inhibited the expression of p-JAK2/p-STAT3 (P<0.05), down-regulated the levels of IL-6 and TNF-α (P<0.001 or P<0.01), and up-regulated IL-10 and HMGB1 compared with I/R group (P<0.01). Compared with TAK-242 group, AG490 could increase the cardioprotection of TAK-242, such as increasing myocardial contractility, diminishing myocardial infarction size and inflammatory cell infiltration, and down regulating p-JAK2/p-STAT3. Additionally, serum levels of IL-6 and TNF-α were down regulated (P<0.01 or P<0.05) and serum concentrations of IL-10 and HMGB1 up regulated (P<0.01 or P<0.05) in AG490 group.CONCLUSION TLR4 antagonist TAK-242 inhibits I/R inflammatory response in mice which may be associated with the inactivation of JAK2/STAT3 signaling pathway.