VEGF-C在慢性疼痛所致认知功能障碍中的作用

Role of VEGF-C in Cognitive Dysfunction Caused by Chronic Pain

目的研究慢性疼痛时VEGF-C水平变化,并探究其在慢性疼痛所致的认知功能障碍中的作用。方法随机将60只8周龄的SD大鼠分为两组,对照组不做任何处理,实验组构建慢性疼痛认知功能障碍模型,Morris水迷宫法评估所有大鼠实验前后的学习记忆功能,ELISA法检测血清VEGF-C浓度、Western Blot检测大鼠海马体的GFAP、Nestin、NeuN蛋白在脑组织中的表达;体外分离原代星形胶质细胞以及神经干细胞,根据是否转染VEGF-C重组载体,将细胞分为敲减组、过表达组和空载组,检测组3细胞对其共培养神经干细胞的分化以及轴突发育以及神经干细胞周期的影响,Western Blot检测各组GFAP、Nestin、NeuN的表达水平。结果Morris水迷宫实验结果显示,与对照组相比,实验组大鼠出现认知功能障碍;血清VEGF-C浓度较对照组有减少;Western Blot显示实验组GFAP表达升高、Nestin、NeuN表达均降低;细胞实验中,在敲减组降低星形胶质细胞中VEGF-C的分泌水平后,共培养的神经干细胞分化以及轴突发育均减慢,细胞分裂减缓。Western Blot检测结果显示,敲减组GFAP表达升高、Nestin、NeuN表达降低,过表达组趋势与之相反。以上差异均有统计学意义(P<0.05)。结论慢性疼痛模型大鼠VEGF-C分泌减少,而降低星形胶质细胞的VEGF-C表达可影响神经干细胞的分化和轴突发育,神经干细胞周期延长,这可能是导致慢性疼痛引发的认知功能障碍的重要原因。

Objective To study the changes of VEGF-C levels during chronic pain,and explore its role in cognitive dysfunction caused by chronic pain.Methods 608-week-old SD rats were randomly divided into 2 groups.The control group remained unchanged,while the experimental group was constructed to a model of chronic pain cognitive dysfunction.Morris water maze was used to evaluate the learning and memory function of all the rats before and after the experiment.The concentration of serum VEGF-C was detected by ELISA,and the expressions of GFAP,Nestin and NeuN proteins in rat hippocampus were detected by Western blot.Primary astrocytes and neural stem cells were isolated in vitro.According to whether VEGF-C recombinant vector was transfected,the cells were divided into knockdown group,overexpression group and empty group.The effects of cells in the three groups on the differentiation,axon development and neural stem cell cycle of co-cultured neural stem cells were detected.The expressions of GFAP,Nestin and NeuN were detected by Western blot.Results Morris water maze test showed that compared with the control group,the rats in the experimental group showed cognitive dysfunction;The concentration of serum VEGF-C was lower than that in the control group;and the concentration of serum VEGF-C in this group decreased.Western Blot showed that that expression of GFAP increased,while the expression of Nestin and NeuN decreased in the experimental group.In the cell experiment,after the knockdown group reduced the secretion level of VEGF-C in astrocytes,the differentiation and axon development of co-cultured neural stem cells slowed down,and so did the cell division.The results of Western blot showed that the expression of GFAP increased and the expression of Nestin and NeuN decreased in the knockdown group,but the trend was opposite in the overexpression group.The above differences were statistically significant(P<0.05).Conclusion Decreased secretion of VEGF-C in rats with chronic pain and decreased expression of VEGF-C in astrocytes can affect the differentiation and axon development of neural stem cells,and prolong the cycle of neural stem cells,which may be an important reason for cognitive dysfunction caused by chronic pain.