Inflammation contributes to mitochondrial dysfunction and neuronal apoptosis. The aim of this study was to determine whether insulin-like growth factor-1 (IGF-1) alleviates mitochondrial apoptosis in lipopolysaccharide (LPS)-treated PC-12 cells, and to further explore the mechanism involved. Prepared PC-12 cells were treated with IGF-1, Mdivi-1 (DRP1 blocker), LY294002 (PI3K blocker), betulinic acid (NF-κB activator) or their combinations. Mitochondrial membrane potential and ATP generation were then measured to assess mitochondrial function. The rate of apoptosis was determined using flow cytometry. The expression of several apoptosis proteins (i.e. Bax, cleaved caspase-9 and cleaved caspase-3) and signaling proteins (i.e. p-GSK3β, NF-κB and NLRP3) was measured using western blotting. Compared with the control cells, the LPS-treated cells showed evidence of mitochondrial dysfunction, increased apoptosis and upregulation of apoptosis proteins, which were significantly alleviated by Mdivi-1. These findings indicate that neuronal apoptosis was activated partly through the mitochondrial pathway. IGF-1 treatment inhibited mitochondrial apoptosis in a dose-dependent manner in the LPS-treated cells. The reagent also increased the expression of p-GSK3β and decreased the expression of NF-κB and NLRP3. Both LY294002 and betulinic acid reversed the protective effect of IGF-1. In addition, LY294002 affected the expression of the three signaling proteins, while betulinic acid only affected the expression of NF-κB and NLRP3. These findings indicated a GSK3β/NF-κB/NLRP3 signaling pathway was existed and was involved in the protective mechanism of IGF-1. In conclusion, IGF-1 alleviated mitochondrial apoptosis through GSK3β/NF-κB/NLRP3 signaling pathway in LPS-treated PC-12 cells.

炎症会导致线粒体功能障碍和神经元凋亡。本研究的目的是确定胰岛素样生长因子-1 (IGF-1) 是否减轻脂多糖 (LPS) 处理的 PC-12 细胞中的线粒体凋亡，并进一步探索所涉及的机制。制备的 PC-12 细胞用 IGF-1、Mdivi-1（DRP1 阻滞剂）、LY294002（PI3K 阻滞剂）、桦木酸（NF-κB 激活剂）或它们的组合处理。然后测量线粒体膜电位和 ATP 生成以评估线粒体功能。使用流式细胞术测定细胞凋亡率。使用蛋白质印迹法测量了几种凋亡蛋白（即 Bax、cleaved caspase-9 和 cleaved caspase-3）和信号蛋白（即 p-GSK3β、NF-κB 和 NLRP3）的表达。与对照细胞相比，LPS 处理的细胞显示出线粒体功能障碍、细胞凋亡增加和细胞凋亡蛋白上调的证据，Mdivi-1 可显着缓解这些问题。这些发现表明神经元凋亡部分通过线粒体途径被激活。在 LPS 处理的细胞中，IGF-1 处理以剂量依赖性方式抑制线粒体凋亡。该试剂还增加了 p-GSK3β 的表达并降低了 NF-κB 和 NLRP3 的表达。LY294002 和桦木酸都能逆转 IGF-1 的保护作用。此外，LY294002 影响三种信号蛋白的表达，而桦木酸仅影响 NF-κB 和 NLRP3 的表达。这些发现表明 GSK3β/NF-κB/NLRP3 信号通路存在并参与 IGF-1 的保护机制。综上所述，