Dept. of Surgery, East Tennessee State Univ., Johnson City, TN 37614-0575, USA.
Am J Physiol Heart Circ Physiol. 2010 Mar;298(3):H984-91. doi: 10.1152/ajpheart.01109.2009. Epub 2010 Jan 8.
Myocardial dysfunction is a major consequence of septic shock and contributes to the high mortality of sepsis. In the present study, we examined the effect of Toll-like receptor 2 (TLR2) ligands, peptidoglycan (PGN), and Pam3CSK4 (Pam3) on cardiac function in cecal ligation and puncture (CLP)-induced sepsis in mice. We also investigated whether the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway is involved in the effect of TLR2 ligands on cardiac function in CLP mice. PGN was administered to C57B6/L mice 1 h before the induction of CLP. Sham surgically operated mice served as a control. Cardiac function indexes (rate of change in left ventricular pressure, stroke work, cardiac output, and ejection fraction) were examined by a microconductance pressure catheter. Cardiac function was significantly decreased 6 h after CLP-induced sepsis compared with sham-operated control. In contrast, PGN administration attenuated CLP-induced cardiac dysfunction. Importantly, the therapeutic treatment with Pam3 1 h after CLP also significantly attenuated cardiac dysfunction in CLP mice. However, the beneficial effect of TLR2 ligands on cardiac dysfunction in CLP-mice was abolished in TLR2-deficient mice. PGN administration significantly increased the levels of phospho-Akt and phospho-GSK-3beta in the myocardium compared with the levels in untreated CLP mice. PI3K inhibition abolished the PGN-induced attenuation of cardiac dysfunction in CLP mice. In conclusion, these data demonstrate that the administration of TLR2 ligands, PGN, or Pam3 attenuates cardiac dysfunction in septic mice via a TLR2/PI3K-dependent mechanism. More significantly, Pam3 therapeutic treatment will have a potential clinical relevance.
心肌功能障碍是脓毒症性休克的主要后果,并导致脓毒症的高死亡率。在本研究中,我们研究了 Toll 样受体 2(TLR2)配体、肽聚糖(PGN)和 Pam3CSK4(Pam3)对盲肠结扎和穿刺(CLP)诱导的脓毒症小鼠心脏功能的影响。我们还研究了 PI3K/Akt 信号通路是否参与 TLR2 配体对 CLP 小鼠心脏功能的影响。PGN 在 CLP 诱导前 1 小时给予 C57B6/L 小鼠。假手术操作的小鼠作为对照。通过微电导压力导管检测心脏功能指数(左心室压力变化率、stroke work、心输出量和射血分数)。与假手术对照组相比,CLP 诱导的脓毒症 6 小时后心脏功能明显降低。相反,PGN 给药可减轻 CLP 诱导的心脏功能障碍。重要的是,CLP 后 1 小时给予 Pam3 的治疗性治疗也显著减轻 CLP 小鼠的心脏功能障碍。然而,TLR2 配体对 CLP 小鼠心脏功能障碍的治疗作用在 TLR2 缺陷型小鼠中被消除。PGN 给药可显著增加未经处理的 CLP 小鼠心肌中磷酸化 Akt 和磷酸化 GSK-3β的水平。PI3K 抑制消除了 PGN 诱导的 CLP 小鼠心脏功能障碍的减轻。总之,这些数据表明,TLR2 配体、PGN 或 Pam3 通过 TLR2/PI3K 依赖性机制减轻脓毒症小鼠的心脏功能障碍。更重要的是,Pam3 的治疗性治疗将具有潜在的临床相关性。