褪黑素调控Nrf2/ARE信号通路延缓髓核间充质干细胞退变的实验研究

  目的  探讨褪黑素对氧化应激条件下的大鼠髓核间充质干细胞(NPMSCs)的影响及调节机制。  方法  使用差速贴壁法获取大鼠NPMSCs。显微镜下观察细胞状态，鉴定第三代细胞三系分化潜能和细胞表面免疫标志物；采用CCK-8法检测不同浓度过氧化氢和褪黑素诱导对大鼠NPMSCs活力的影响确定最佳浓度和实验分组；免疫荧光和流式细胞学技术检测NPMSCs活性氧水平；免疫印迹分析外基质标志蛋白(Ⅱ型胶原、糖胺聚糖)和通路核心蛋白(Nrf2、HO-1)表达情况。  结果  褪黑素在氧化应激下保护了NPMSCs的活性，且1 μmol/L浓度保护效应最为明显(0.717±0.018，t=7.102, P＜0.01)。褪黑素可抑制NPMSCs在H₂O₂诱导后的活性氧水平(阳性率70.0% vs. 32.7%)。此外，褪黑素还能显著提高Nrf2/ARE信号通路中关键蛋白核因子E2相关因子(1.925±0.024，t=13.150，P＜0.01)和血红素氧合酶-1(1.605±0.019，t=12.940, P＜0.01)的活性，改善NPMSCs的功能。褪黑素治疗后，细胞基质蛋白Ⅱ型胶原(0.850±0.010，t=25.200，P＜0.01)和糖胺聚糖(0.335±0.013，t=10.640，P＜0.01)表达增加。  结论  褪黑素通过调控Nrf2/ARE信号通路可以影响NPMSCs退变的生物学特性。 

Melatonin regulates Nrf2/ARE signal pathway to delay the degeneration of nucleus pulposus mesenchymal stem cells

  Objective  To explore the effect of melatonin on rat nucleus pulposus mesenchymal stem cells (NPMSCs) under oxidative stress and its regulatory mechanism.  Methods  Rat nucleus pulposus mesenchymal stem cells were isolated and purified by differential adhesion method. The state of cells was observed under the microscope to identify the differentiation potential of the third generation cells and cell surface immune markers. CCK-8 method was used to detect the effect of different concentrations of hydrogen peroxide and melatonin on the activity of NPMSCs in rats to determine the optimal concentration and experimental grouping. The level of reactive oxygen species in NPMSCs were detected by immunofluorescence and flow cytometry. The expressions of extracellular matrix marker proteins (collagen Ⅱ and glycosaminoglycan) and key proteins (Nrf2, HO-1) in Nrf2/ARE signaling pathway were analyzed by Western blotting.  Results  Melatonin protected the activity of NPMSCs under oxidative stress, and the protective effect of 1 μmol/L concentration was the most obvious (0.717±0.018, t=7.102, P < 0.01). Melatonin could inhibit the level of reactive oxygen species induced by H₂O₂ (positive rate: 70.0% vs. 32.7%). In addition, melatonin significantly increased the activities of Nrf2 (1.925±0.024, t=13.150, P < 0.01) and HO-1 (1.605±0.019, t=12.940, P < 0.01), and improved the function of NPMSCs. After treatment with melatonin, the expression of Collagen Ⅱ (0.850±0.010, t=25.200, P < 0.01) and glycosaminoglycan (0.335±0.013, t=10.640, P < 0.01) increased.  Conclusion  Melatonin affects the biological characteristics of NPMSCs degeneration by regulating Nrf2/ARE signal pathway.