疼痛调控相关miRNAs的筛选及脊髓miR-29c对神经病理性痛大鼠痛阈的影响

Screening of pain regulation related miRNAs and effects of spinal miR-29c on neuropathic pain in rats

目的通过microRNAs(miRNAs)芯片技术筛选疼痛调控相关的miRNAs,观察microRNA-29c(miR-29c)对神经病理性痛大鼠痛阈的影响。方法实验一:雌性SD大鼠,随机分为神经病理性痛组(SNI组)及妊娠神经病理性痛组(PSNI组),测定机械缩足阈值(MWT),观察分娩对疼痛的影响。在SNI组及PSNI组大鼠分娩后MWT差异显著时,取脊髓腰膨大组织,筛选差异表达的miRNAs。实验二:选取目的miRNAs,包被过表达或沉默慢病毒,脊髓内注射干预后观察SNI组大鼠MWT变化。结果与SNI组大鼠比较,PSNI组大鼠分娩后第3天MWT明显升高,脊髓c-Fos蛋白含量明显降低(P<0.05);miRNAs芯片分析共发现71条差异表达的miRNAs,在PSNI大鼠显著上调37条,显著下调34条;选取并包被miR-124a过表达、miR-29c沉默慢病毒注射,miR-29c表达沉默可明显提高SNI组大鼠MWT。结论miR-29c是通过基因芯片筛选获得的miRNA,下调SNI大鼠脊髓miR-29c表达,能够显著改善病理性痛状态。

Objective To explore the pain regulation related microRNAs(miRNAs),and the effects on hyperalgesia in neuropathic pain rat model.Methods Step 1:adult female SD rats were randomly divided into two groups:spared nerve injury(SNI)neuropathic pain model group(group SNI)and SNI with pregnancy group(group PSNI).The paw mechanical withdrawal threshold(MWT)was measured to explore the effects of delivery on hyperalgesia.And lumbar enlargement spinal tissue of SNI and PSNI rats were obtained when there were significant differences of pain threshold between groups.Then these tissues were sent for miRNAs gene analysis,looking for differentially expressed miRNAs.Step 2:the functional miRNAs were discovered by observing the changes of pain threshold after intraspinal injection of lentiviruses in SNI rats.And the bioinformatics and target gene of pain-related miRNAs were analysized.Results Compared with group SNI,MWT was significantly decreased and a pain relief was observed on day 3 after childbirth in group PSNI(P<0.05).The results of miRNAs gene analysis showed 71 largely different expressional miRNAs,including 37 up-regulated miRNAs and 34 down-regulated miRNAs in group PSNI.Then the up-regulated miR-124 a and down-regulated miR-29 c were chosen for the functional research through spinal injection of overexpressed miR-124 a lentiviruse and silenced miR-29 c lentiviruses in SNI rats.Increased pain threshold in silenced miR-29 c SNI rats indicating a pain mediated role of miR-29 c.Conclusion Spinal miR-29 c is obtained from label-free quantification,specific down-expression of miR-29 c in the spinal tissue can notably raise the pain threshold of SNI rat model,prompting the potential role of miR-29 c in the pain relief process.