目的 探讨miR-21-5p在早期不良生活事件诱发肠易激综合征（IBS）内脏超敏中的作用及其机制。方法 通过母婴分离方法制备早期不良生活事件诱发成年内脏超敏大鼠模型,利用微RNA（miRNA）芯片结合定量聚合酶链反应（qPCR）筛选大鼠背根神经节（DRG）神经元中差异表达miRNA,通过生物信息学分析结合荧光素酶报告基因检测实验寻找差异表达miRNA的下游靶标,采用细胞和动物实验相结合来验证差异表达miRNA通过下游靶标参与母婴分离诱发成年大鼠内脏超敏的过程。结果 miR-21-5p显著高表达于母婴分离所致成年内脏超敏大鼠DRG神经元中（P<0.05）。生物信息学分析、荧光素酶报告基因检测和细胞实验提示转化生长因子β诱导（TGFBI）基因是miR-21-5p的靶基因。在细胞水平,miR-21-5p模拟物干预后DRG神经元内TGFBI蛋白水平显著下降（P<0.05）,miR-21-5p抑制剂干预后DRG神经元内TGFBI蛋白水平显著升高（P<0.05）。在整体动物水平,miR-21-5p激动剂干预后大鼠内脏敏感性较对照组显著升高（P<0.05）,TGFBI蛋白水平显著下降（P<0.05）;miR-21-5p拮抗剂干预后大鼠内脏敏感性较对照组显著下降（P<0.05）,TGFBI蛋白水平显著升高（P<0.05）。结论 大鼠DRG中miR-21-5p通过抑制TGFBI表达,促进母婴分离诱发的内脏超敏,从而参与早期不良生活事件诱发成年IBS。
Objective To investigate the role of miR-21-5p in early adverse life events （EALs）-induced visceral hypersensitivity of irritable bowel syndrome （IBS） and its mechanism. Methods A rat model of visceral hypersensitivity induced by EALs in adult rats was established by mother-infant separation. MicroRNA （miRNA） microarrays combined with quantitative polymerease chain reaction （qPCR） were used to screen for differential miRNAs in dorsal root ganglion （DRG） neurons, and bioinformatics analysis combined with luciferase reporter gene assay was performed to search for downstream targets of the differential miRNAs. Cellular and animal experiments were combined to verify if the differential miRNAs were involved in mother-infant separation-induced visceral hypersensitivity through the downstream targets. Results MiR-21-5p was significantly overexpressed in the DRG neurons of mother-infant separation-induced adult visceral hypersensitivity rats （P<0.05）. Bioinformatics analysis, luciferase reporter gene assay, and cellular experiments suggested that transforming growth factor beta induction （TGFBI） gene was a miR-21-5p target gene. At the cellular level, the TGFBI protein level in DRG neurons was significantly decreased after miR-21-5p mimic intervention （P<0.05）, and significantly increased after miR-21-5p inhibitor intervention （P<0.05）. At the animal level, the visceral sensitivity was significantly higher （P<0.05） and TGFBI protein level was significantly lower （P<0.05） in rats after miR-21-5p agonist intervention compared with the control group,and visceral sensitivity was significantly lower （P<0.05） and the TGFBI protein level was significantly higher （P<0.05） in rats after miR-21-5p antagonist intervention compared with the control group. Conclusion MiR-21-5p in rat DRG promotes mother-infant separation-induced visceral hypersensitivity by inhibiting TGFBI expression, and thus participates in the development of adult IBS induced by EALs.
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