Department of Kinesiology, College of Natural Science, Jeju National University, Jeju 63243, Korea.
Laboratory of Veterinary Toxicology, College of Veterinary Medicine, Jeju National University, Jeju 63243, Korea.
Int J Environ Res Public Health. 2021 Aug 26;18(17):8988. doi: 10.3390/ijerph18178988.
Sciatic nerve injury (SNI) leads to sensory and motor dysfunctions. Nobiletin is a major component of polymethoxylated flavonoid extracted from citrus fruits. The role of nobiletin on sciatic nerve regeneration is still unclear. Thus, the purpose of this study was to investigate whether nobiletin increases DRG neurite elongation and regeneration-related protein expression after SNI. Cytotoxicity of nobiletin was measured in a concentration-dependent manner using the MTT assay. For an in vitro primary cell culture, the sciatic nerve on the middle thigh was crushed by holding twice with forceps. Dorsal root ganglion (DRG) and Schwann cells were cultured 3 days after SNI and harvested 36 h later and 3 days later, respectively. In order to evaluate specific regeneration-related markers and axon growth in the injured sciatic nerve, we applied immunofluorescence staining and Western blot techniques. Nobiletin increased cell viability in human neuroblastoma cells and inhibited cytotoxicity induced by exposure to HO. Mean neurite length of DRG neurons was significantly increased in the nobiletin group at a dose of 50 and 100 μM compared to those at other concentrations. GAP-43, a specific marker for axonal regeneration, was enhanced in injury preconditioned Schwann cells with nobiletin treatment and nobiletin significantly upregulated it in injured sciatic nerve at only 3 days post crush (dpc). In addition, nobiletin dramatically facilitated axonal regrowth via activation of the BDNF-ERK1/2 and AKT pathways. These results should provide evidence to distinguish more accurately the biochemical mechanisms regarding nobiletin-activated sciatic nerve regeneration.
坐骨神经损伤 (SNI) 可导致感觉和运动功能障碍。川陈皮素是从柑橘类水果中提取的多甲氧基黄酮的主要成分。川陈皮素在坐骨神经再生中的作用尚不清楚。因此，本研究旨在探讨川陈皮素是否能增加 SNI 后 DRG 轴突伸长和再生相关蛋白的表达。采用 MTT 法在浓度依赖性方式下测量川陈皮素的细胞毒性。对于体外原代细胞培养，用镊子夹住大腿中段的坐骨神经，夹住两次。SNI 后 3 天培养背根神经节 (DRG) 和施万细胞，分别在 36 小时和 3 天后收获。为了评估损伤坐骨神经中特定的再生相关标记物和轴突生长，我们应用免疫荧光染色和 Western blot 技术。川陈皮素在人神经母细胞瘤细胞中增加细胞活力，并抑制暴露于 HO 引起的细胞毒性。与其他浓度相比，在 50 和 100 μM 剂量下，川陈皮素组 DRG 神经元的平均轴突长度明显增加。用川陈皮素处理的损伤前条件化施万细胞中 GAP-43（轴突再生的特异性标记物）增强，而在损伤后仅 3 天（dpc），川陈皮素明显上调其在损伤坐骨神经中的表达。此外，川陈皮素通过激活 BDNF-ERK1/2 和 AKT 通路显著促进轴突再生。这些结果应该为更准确地区分与川陈皮素激活坐骨神经再生有关的生化机制提供证据。
