中文摘要：

目的从microRNA（miR）组学角度探讨坐骨神经预损伤促进脊髓后索损伤修复的机制，以期寻找关键治疗靶点。方法健康雌性Wistar大鼠48只，按随机数字表法分为坐骨神经预损伤＋脊髓后索损伤组（15只）、单纯脊髓后索损伤组（15只1、单纯坐骨神经损伤组（15只）和对照组（3只1。在脊髓后索损伤前7d切断大鼠双侧坐骨神经，脊髓后索损伤后4h、1d、3d、7d每组取3只大鼠处死并取与双侧坐骨神经对应的背根神经节，miR芯片分析miR表达谱：实时定量逆转录聚合酶链式反应依T—qeCR）检测miR-182、cAMP应答元件结合蛋白fCREB）mRNA的表达；Western成blotting、ELISA分别检测CREB、p-CREB蛋白的表达和cAMP含量：脊髓后索损伤后14d取损伤段脊髓，HE染色，免疫组化染色检测脊髓后索神经丝蛋白NF-200的表达。结果与对照组相比，坐骨神经损伤＋脊髓后索损伤组、单纯脊髓后索损伤组大鼠损伤后不同时间共有681个miRNA表达发生变化。与单纯脊髓后索损伤组比较，坐骨神经损伤＋脊髓后索损伤组损伤后3d和7dmiR．182表达下调；与对照组相比，单纯坐骨神经损伤组大鼠背根神经节miR-182、坐骨神经损伤＋脊髓后索损伤组背根神经节CREBmRNA的表达均无明显变化，差异无统计学意义（胗0．051；与对照组比较，坐骨神经损伤＋脊髓后索损伤组大鼠损伤后3d、7d背根神经节CREB和P-CREB蛋白表达，4h、1d、3d、7d背根神经节cAMP的含量均增加，差异均有统计学意义（氏0．05）。免疫组化染色检测显示坐骨神经损伤＋脊髓后索损伤组脊髓后索损伤中心尾端NF200表达比单纯脊髓后索损伤组增加，差异有统计学意义（P〈0．05）。结论坐骨神经预损伤促进脊髓后索损伤的修复．机制与背根神经节中miR-182下调、cAMP上调．从而导致磷酸化CREB蛋白增加有关．

英文摘要：

Objective To explore the repairment mechanism of dorsal column lesion which is promoted by sciatic nerve conditioning injury on the basis of microRNA genomics to find the key therapeutic target. Methods Forty-eight healthy female Wistar rats were randomly divided into sciatic nerve conditioning injury group （n=15）, simple dorsal column lesion group （n=15）, simple sciatic nerve injury group （n=15） and control group （n=3）. Sciatic neurotomy was performed 7 d before giving dorsal column lesion in rats from the sciatic nerve conditioning injury group and simple dorsal column lesion group; and then, rats from the four groups were sacrificed and excised the bilateral dorsal root ganglions （DRGs） connected with bilateral sciatic nerves 4 h, and 1, 3 and 7 d after giving dorsal column lesion. Microarray was used to investigate microRNA expression profiles, real time-quantitative PCR was applied to detect the expression of miR-182, ELISA was employed to detect the cyclic adenosine monophosphate （cAMP） level, and Western blotting was used to detect the protein expressions of cAMP-response element binding （CREB） and phosphorylating-CREB （p-CREB）. The injured spinal cord segments （10^th thoracic spinal cord segments） were obtained 14 d after giving dorsal column lesion, Hematoxylin and eosin （HE） stainning was used to observe the morphology of nerve fiber bundles, and immunohistochemistry was used to investigate the expression of neurofilament protein NF-200 in dorsal colunm. Results As compared with control group, there were 681 changed miRNAs at different check points in the sciatic nerve conditioning injury group and simple dorsal column lesion group. As compared with that in the simple dorsal column lesion group, miR-182 level in the sciatic nerve conditioning injury group was down-regulated 3 and 7 d after giving dorsal column lesion （P〈0.05）. As compared with those in the control group, miR-182 in the DRGs from simple sciatic nerve conditioning injury group and CREB mRNA ex