目的 探讨 AMPK 信号通路在白介素-6(IL-6)诱导的肿瘤恶液质骨骼肌衰减中的作用,并评估左旋肉碱(LC)对肿 瘤恶液质骨骼肌衰减的抑制效应,以及这一效应是否经由 AMPK 信号通路。 方法 采用 200 ng / ml IL-6 诱导 C2C12 成肌细胞 衰减,以此建立肿瘤恶液质骨骼肌衰减的体外细胞模型。 实验分为 C 组(不予干预)、IL-6 组( 200 ng / ml IL-6 处理 2 h) 、 IL-6+LC 组( 200 ng / ml IL-6 处理 2 h 后,LC 干预 24 h),观察 LC 对肿瘤恶液质骨骼肌衰减的防治效果。 结晶紫染色 C2C12 细胞,评估 LC 对肌管衰减的作用; RT-PCR 检测 p70S6K、MuRF1 和 Atrogin-1 的转录水平,评估 LC 对肿瘤恶液质骨骼肌衰减 的影响;蛋白质印迹法分析 C2C12 细胞 AMPK/ mTOR/ FOXO1 信号通路蛋白的表达和磷酸化水平,探讨 LC 缓解 IL-6 诱导骨 骼肌衰减的可能机制。 8 周龄 C57 小鼠腹腔接种结肠癌 MC38 细胞,建立体内肿瘤恶液质模型。 实验分为 MC38+LC 组和 MC38+ddH2O 组,每组各 8 只 C57 小鼠,MC38+LC 组每天通过灌胃给予 5 mg / kg 剂量的 LC,MC38+ddH2O 组每天通过灌胃给 予等体积的 ddH2O。 通过旷场实验、握力实验和 ELISA 分别评估小鼠体能、肌力和血清 IL-6 水平。 结果 体外实验中,与 C 组 相比,IL-6 组肌管直径减少(P<0. 05),MuRF1 和 Atrogin-1 的转录水平上调(P<0. 05),AMPK 的磷酸化升高(P< 0. 05), mTOR、p70S6K、FOXO1 的磷酸化降低(P<0. 05),而 LC 可以逆转这些效应。 体内实验中,MC38+LC 组小鼠较 MC38+ddH2O 组 移动距离增加(178. 29%,P<0. 05),肌力增加(62. 74%,P<0. 05),血清中 IL-6 水平降低(P<0. 05)。 结论 左旋肉碱可能经由 AMPK/ mTOR/ FOXO1 信号通路抑制 IL-6 诱导的肿瘤恶液质骨骼肌衰减。

Objective This study aimed to elucidate the role of the AMPK signaling pathway in interleukin-6 IL-6 -induced skeletal muscle atrophy and to evaluate the inhibitory effect of L-carnitine LC on tumor cachexia-induced skeletal muscle atrophy as well as whether this effect is mediated through the AMPK signaling pathway. Method C2C12 myoblasts were induced to atrophy with 200 ng / ml IL-6 to establish an in vitro cellular model of tumor cachexia-induced skeletal muscle decline. The experiment was divided into control group IL-6 group and IL-6+LC treatment group to observe the effects of LC on the prevention and treatment of tumor cachexia-induced skeletal muscle atrophy C2C12 cells were stained with crystal violet to assess the effect of LC on myotube atrophy RT-PCR was used to detect the transcription levels of p70S6K MuRF1 and Atrogin - 1 to assess the effect of LC on tumor cachexia-induced skeletal muscle decline Western blot analysis was used to examine the expression and phosphorylation levels of AMPK/ mTOR/ FOXO1 signaling pathway proteins in C2C12 cells to explore the possible mechanism by which LC alleviates IL- 6- induced skeletal muscle decline. An in vivo tumor cachexia model was established by intraperitoneal injection of colon cancer MC38 cells in 8-week-old C57 mice. The experiment was divided into MC38+LC group and MC38+ddH2O group with daily intragastric administration of 5 mg / kg LC or an equivalent volume of ddH2O. The mice's physical fitness muscle strength and serum IL-6 levels were tested by open field test grip strength test and ELISA respectively. Result In vitro compared to the control group the IL-6 group showed a reduction in myotube diameter P< 0. 05 upregulation of MuRF1 and Atrogin- 1 transcriptional levels P<0. 05 increased phosphorylation of AMPK P<0. 05 and decreased phosphorylation of mTOR p70S6K and FOXO1 P<0. 05 with LC reversing these effects. In vivo mice in the MC38+LC group exhibited increased movement distance 178. 29% P<0. 05 enhanced muscle strength 62. 74% P< 0. 05 and lower serum IL - 6 levels P< 0. 05 compared to the MC38 + ddH2O group. Conclusion L-carnitine may inhibit interleukin-6-induced tumor cachexia skeletal muscle decline through the AMPK/ mTOR/ FOXO1 signaling pathway.