百里醌通过激活SIRT1/STAT3通路对脓毒症所致大鼠肝损伤和糖代谢紊乱的保护作用

Protective effects of thymoquinone on sepsis-induced liver injury and glucose metabolism disorder in rats by activating SIRT1/STAT3 pathway

摘要:

目的： 评估百里醌对脓毒症大鼠的治疗潜力，探讨其潜在的分子机制。方法： 盲肠结扎穿刺（cecum ligation and puncture，CLP）诱导大鼠脓毒症模型，CLP术后每12 h经腹腔注射百里醌（20 mg/kg），持续3 d，同时腹腔注射或不注射沉默信息调节因子1（sirtuin1，SIRT1）抑制剂EX527（5 mg/kg）。检测大鼠空腹血糖和空腹胰岛素水平；利用赖氏分析法测定大鼠血清中天冬氨酸转氨酶（aspartate aminotransferase，AST）及丙氨酸转氨酶（alanine aminotransferase，ALT）含量；利用免疫组化测定大鼠肝组织中白细胞介素-6（interleukin-6，IL-6）和肿瘤坏死因子α（tumor necrosis factor-α，TNF-α）含量；Western blot测定p-Akt、t-Akt、SIRT1、p-信号转导因子和转录激活因子3（signal transducer and activator of transcription 3，STAT3）、PEPCK、G6Pase和t-STAT3的含量；DCFH-DA荧光探针法测定肝脏组织内活性氧（reactive oxygen species，ROS）表达；免疫沉淀反应分析乙酰化STAT3在肝组织中的表达。结果： 脓毒症大鼠肝脏SIRT1/STAT3通路明显受到抑制，AST、ALT、IL-6和TNF-α表达上调，血糖和胰岛素水平升高；百里醌可促进肝脏SIRT1表达和STAT3磷酸化，减轻脓毒症导致的肝功能障碍和糖代谢紊乱；EX527显著降低百里醌对脓毒症引起的肝损伤、糖代谢紊乱和STAT3失活的保护作用。结论： 百里醌可作为一种潜在治疗脓毒症导致肝功能损害和糖代谢紊乱的药物，其作用机制可能通过激活肝脏SIRT1/STAT3通路来实现。

Abstract:

Objective: To evaluate the therapeutic potential of thymoquinone in rats with sepsis and explore the underlying molecular mechanism. Methods: Cecum ligation and puncture (CLP) was used to induce sepsis rats model. Thymoquinone (20 mg/kg) was intraperitoneally injected every 12 h for three days after CLP, with or without intraperitoneal injection of the sirtuin1 (SIRT1) inhibitor EX527 (5mg/kg). The expression of fasting blood glucose and fasting insulin were detected after the designed treatment. The relative expression of aspartate aminotransferase (AST) and lactic alanine transaminase (ALT) in serum were determined by Reit’s analysis method. Levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in liver tissues were analyzed by immunohistochemistry. Levels of p-Akt, t-Akt, SIRT1, p-signal transducer and activator of transcription 3 (STAT3), PEPCK, G6Pase and t-STAT3 were evaluated by Western blot. The expression of reactive oxygen species (ROS) in liver tissues was detected by DCFH-DA fluorescence probe and the level of acetylated STAT3 in liver tissues was determined by immunoprecipitation analysis. Results: The hepatic SIRT1/STAT3 pathway of septic rats was significantly inhibited, expressions of AST, ALT, IL-6 and TNF-α were up-regulated, and levels of fasting blood glucose and fasting insulin were increased. Thymoquinone administration was able to promote STAT3 phosphorylation and alleviate liver dysfunction and glucose metabolism disorder. EX527 significantly diminished the protective effect of thymoquinone on sepsis induced liver injury, hyperglycaemia and STAT3 inactivation. Conclusion: Thymoquinone is a potential therapeutic agent for sepsis-associated liver injury and glucose metabolism disorder and its mechanism may be realized by activating SIRT1/STAT3 pathway.