NAD延缓背根神经节轴突变性的实验研究

Nicotinamide adenine dinucleotide prevents axonal degeneration

目的探讨烟酰胺腺嘌呤二核苷酸(NAD)对神经轴突变性的保护作用。方法用长春新碱处理原代培养的背根神经节细胞,建立轴突变性细胞模型,然后加入不同浓度的NAD,观察神经轴突生长状况,MTT检测背根神经节细胞的生长活性,行神经丝蛋白(NF)免疫组化染色观察神经轴突的变化。结果损伤组加入长春新碱8 h后,轴突远端发生典型的轴突变性,12 h后轴突肿胀,断裂,24 h后见不到完整的轴突结构。保护组加入NAD后可明显延缓轴突变性,在12 h后仍能保持比较完整轴突结构,24 h后远端发生轻微变性。MTT结果显示:NAD保护组可提高细胞存活率(P<0.01)。轴突计数显示:NAD保护组在加入长春新碱后12 h,只有35%左右的轴突发生变性,而损伤组却高达60%的轴突发生了变性(P<0.01)。结论NAD对轴突变性具有明显的保护作用,可延缓轴突变性。

Objective To explore the effect of nicotinamide adenine dinucleotide （NAD） in delaying axonal degeneration. Methods Dorsal root ganglion（DRG） cells were isolated from neonate rats and cultured in DMEM/F12 medium, and then treated with vincrisfine to establish an axonal degeneration model. NAD of different concentrations was added in the culture medium to detect its protective effects. Mona] degeneration was identified by immunocytocheraical staining and by MqT analysis, and length and number of DRG cells were determined using the software IPP. Results DRG cells treated with vineristine suffered typical axonal degeneration in the distal end of the axon at 8h in vitro. The axon was swollen and disrupted at 12 h. There was no intact axonal structure after a 24 h-treatment with vincristine. The end of the axon had normal axonal structure at 12 h in culture, and the axon had light degeneration at 24 h in vitro culture. MTT analysis showed that the experimental groups containing NAD had higher cell survival rates than the injury groups. Axon counting showed that only 35% of axons degenerated in the experimental groups, while only 60% of axons degenerated in the injury groups. Conclusion NAD plays an important role in preventing axonal degeneration.