神经病理性疼痛大鼠海马miRNA差异性表达研究

目的:探讨神经病理性疼痛大鼠海马差异性表达的miRNAs,并预测其在神经病理性疼痛发病机制中的作用。方法:通过建立L5神经结扎横切(L5 Spinal Nerve Transection,L5-SNT)所致神经病理性疼痛大鼠模型,在机械痛阈检测结束后处死大鼠,剥离海马组织,提取miRNA进行测序,找出L5-SNT大鼠海马差异表达的miRNAs,并对其进行靶基因预测及功能分析。结果:L5-SNT大鼠模型建立成功,手术侧足底机械痛阈明显低于正常组和假手术组大鼠(P0.05)。miRNA测序结果显示:L5-SNT组的大鼠海马miRNAs发生明显的差异性表达,其中显著下调的为:rno-miR-30c-2-3p、rno-miR-370-3p、rno-miR-541-3p、rno-miR-22-3p(P0.05);显著上调miRNAs为:rno-miR-32-5p(P0.05);对上述差异性表达明显的miRNAs进行靶基因预测及功能分析,推测与海马神经病理性疼痛有关的靶基因有:Mapk14、Camk2b、Ntrk2、Cxcl12。结论:L5-SNT大鼠海马的差异性miRNAs及其靶基因功能可能主要与海马MAPK信号通路、长时程增强、炎症反应及细胞周期有关。

Differential Expression of miRNA in the Hippocampus of Rats with Neuropathic Pain

ABSTRACT Objective: To explored the differenial expression of miRNAs in hippocampus of rat suffered from neuropathic pain, and further deduce the role of them in the neuropathic pain. Methods: L5 spinal nerve transection induced-neuropathic pain of rat models (L5-SNT) were used in this study. After finishing the behavioral test, rats were euthanized and the hippocampi were harvested rapidly for miRNA extraction. The miRNAs which changed most significantly in the hippocampus were found out, and then speculate its pain-asso- ciated target gene using miRNA databases. Results: The neuropathic pain model was successfully established, whose threshold of me- chanical pain sensitivity reduced significantly compared with the control group and the sham-operated group(P<0.05). Microarray showed that the expression of miRNAs in L5-SNT group significantly changed, the expression of rno-miR-30c-2-3p, rno-miR-370-3p, rno-miR-541-3p and rno-miR-22-3p were significantly down-regulated (P<0.05) and the expression of rno-miR-32-5p was significantly up-regulated(P<0.05). After target gene prediction and function analysis of miRNAs which changed dramatically in the experiment, we hypothesized that following target gene was pain-associated: Mapk14, Camk2b, Ntrk2, Cxcl12. Conclusion: The changes of miRNAs expression and its target genes function in the hippocampus of L5-SNT rats might be related to the MAPK signal pathway, long term po- tentiation, inflammatory response and cell cycle.