Zhang Shuai, Li Dong, Yang Jing-Yan, Yan Ting-Bin
Department of Orthopedics, Qilu Hospital of Shandong University, No. 107 Wenhuaxi Road, Jinan, Shandong, 250012, China.
Cell Stress Chaperones. 2015 Jul;20(4):621-9. doi: 10.1007/s12192-015-0585-0. Epub 2015 May 5.
Long-term and high-dose glucocorticoids (GCs) supplementation has been linked to osteoporosis. In this study, we studied the protective role of plumbagin against GC-induced cell damage in MC3T3-E1 cells. The effect of dexamethasone (DEX) and plumbagin on cell viability was determined. DEX showed as IC-50 value of 95 μM. Further, 10 μM plumbagin treatment effectively ameliorated DEX-induced cell death by increasing the cell viability to 92 %. A further effect of plumbagin on DEX-induced oxidative stress was determined through reactive oxygen species (ROS) level, lipid peroxide content, and antioxidant status. Nrf-2 nuclear localization was analyzed through immunofluorescence. Protein expression of redox regulator Nrf-2 and their target genes HO-1 and NQO1 and osteogenic markers (OCN, OPN Runx-2) were determined by Western blot. Apoptotic effect was analyzed by mitochondrial membrane potential and caspase activities (3, 8, and 9). The results showed that DEX treatment showed a significant increase in oxidative stress through increased ROS levels and downregulation of cytoprotective antioxidant proteins and antioxidant enzyme activities. Further DEX treatment downregulated the osteogenic markers and upregulated apoptosis through decreased mitochondrial membrane potential and upregulation of caspase activities. Plumbagin treatment significantly reversed the levels of oxidative stress and apoptotic markers and protected against DEX-induced cell damage. Further, plumbagin treatment significantly improved the expression of osteogenic markers compared to DEX treatment. In conclusion, the present study shows that plumbagin offers significant protective role against DEX-induced cellular damage via regulating oxidative stress, apoptosis, and osteogenic markers.
长期大剂量补充糖皮质激素（GCs）与骨质疏松症有关。在本研究中，我们研究了白花丹醌对MC3T3-E1细胞中糖皮质激素诱导的细胞损伤的保护作用。测定了地塞米松（DEX）和白花丹醌对细胞活力的影响。DEX的IC-50值为95μM。此外，10μM白花丹醌处理通过将细胞活力提高到92%，有效改善了DEX诱导的细胞死亡。通过活性氧（ROS）水平、脂质过氧化物含量和抗氧化状态，确定了白花丹醌对DEX诱导的氧化应激的进一步影响。通过免疫荧光分析Nrf-2核定位。通过蛋白质印迹法测定氧化还原调节因子Nrf-2及其靶基因HO-1和NQO1以及成骨标志物（骨钙素、骨桥蛋白Runx-2）的蛋白表达。通过线粒体膜电位和半胱天冬酶活性（3、8和9）分析凋亡效应。结果表明，DEX处理通过增加ROS水平和下调细胞保护性抗氧化蛋白及抗氧化酶活性，显著增加了氧化应激。进一步的DEX处理通过降低线粒体膜电位和上调半胱天冬酶活性，下调了成骨标志物并上调了细胞凋亡。白花丹醌处理显著逆转了氧化应激和凋亡标志物的水平，并防止了DEX诱导的细胞损伤。此外，与DEX处理相比，白花丹醌处理显著改善了成骨标志物的表达。总之，本研究表明，白花丹醌通过调节氧化应激、细胞凋亡和成骨标志物，对DEX诱导的细胞损伤具有显著的保护作用。
