膀胱组织中微小RNA-429表达与大鼠脊髓损伤后膀胱癌发生的关系

Reveal relation between microRNA-429 expression in bladder tissue and bladder cancer after spinal cord injury in rats

目的探讨大鼠脊髓损伤后膀胱组织中微小RNA（miRNA）表达与膀胱癌发生的关系。方法选取雌性Wistar大鼠72只，将其中27只完全随机分为脊髓损伤组（12只）、假手术组（12只）和对照组（3只）。脊髓损伤组在脊髓损伤造模后3、6、9、12个月处死取材，假手术组在椎板切除术后3、6、9、12个月处死取材，每个时点3只大鼠，对照组不做任何处理，实验开始时处死后直接取材。比较脊髓损伤组和假手术组大鼠术后3、6、9和12个月以及对照组的膀胱组织中miR-429相对表达量。另取15只大鼠完全随机分配到脊髓损伤后3、6、9、12个月和对照组，各3只，比较对照组和脊髓损伤后3、6、9和12个月大鼠膀胱组织中E2F3蛋白相对表达量。另将18只大鼠不进行脊髓损伤或椎板切除，于喂养6、9和12个月时处死取材，比较其与对照组大鼠miR-429和E2F3蛋白表达情况，验证年龄对miR-429和E2F3蛋白的影响。另有12只大鼠完全随机分配到对照组以及脊髓损伤后1、14d和1个月3个时点，各3只，并与先前的脊髓损伤后3、6、9和12个月大鼠一同用于研究miR-429和E2F3蛋白的表达趋势。结果脊髓损伤组脊髓损伤造模后9、12个月的miR-429相对表达量明显低于对照组（P〈0．05），而miR-429在假手术组中的相对表达量与对照组比较差异无统计学意义（P〉0．05）。脊髓损伤后9、12个月大鼠膀胱组织中E2F3蛋白的相对表达量明显高于对照组（P〈0．05）。与对照组大鼠相比，脊髓损伤后6、9和12个月同时处死的未进行任何造模操作的大鼠膀胱组织中miR-429和E2F3蛋白表达差异均无统计学意义（均P〉0．05）。miR-429和E2F3蛋白在膀胱组织中的表达与年龄无关。将脊髓损伤后1、14d和1、3、6、9、12个月的大鼠膀胱组织的miR-429和E2F3蛋白表达量结合在一起分析发现，miR-429在脊髓损伤6个月后开始下调，而E2F3蛋白的表达在脊髓损伤6个月后开始出现明显的上调。结论大鼠膀胱组织中miR-429在脊髓损伤后下调，导致其靶蛋白E2F3表达上调，增强了肿瘤发生的可能性。

Objective To investigate the relation between microRNA-429 （miR-429）and bladder cancer after spinal cord injury （ SCI ） via analyzing the expression profiling of microRNA genomes （ miRNomes ）. Methods Totally 72 female Wistar rats were selected, 27 rats were completely randomly divided into SCI group （ n = 12） , sham operation group （ n = 12 ） and control group （ n = 3 ） ; rats in SCI group were executed at 3, 6, 9 and 12 months after SCI model; rats in sham operation group were executed at 3, 6, 9 and 12 months after lami- nectomy; rats in control group were executed at the beginning of experiment without any operation. Expressions of miR-429 in bladder tissues were analyzed. 15 rats were completely randomly divided into control group and 3, 6,9 and 12 months after SCI groups, with 3 rats in each group. Expressions of E2F3 protein in bladder tissues were analyzed. Eighteen rats without SCI or laminectomy were executed at 6, 9 and 12 months after SCI. Expressions of miR-429 and E2F3 protein in bladder tissues at those 3 time points were compared. Twelve rats were completely randomly divided into control group and 1 d, 14 d and 1 month after SCI groups to study expression trends of miR-429 and E2F3 protein. Results At 9 and 12 months after SCI, expressions of miR-429 in SCI group were significantly lower than those in control group （ P 〈 0. 05 ） , the difference of miR-429 expression between sham operation group and control group was not significant（ P 〉 0. 05 ） ; expressions of E2F3 protein in SCI group were significantly higher than those in control group （P 〈 O. 05 ）. At 6, 9 and 12 months after SCI, expressions of miR-429 and E2F3 protein in rats without operation had no significant differences compared with control group. There was no correlation between expressions of miR-429, E2F3 protein and age. Expressions of miR-429, E2F3 protein at 1 d, 14 d, 1 month, 3, 6, 9 and 12 months after SCI revealed that the expression of miR-429 decreased and the expression of E2F3 protein significantly increased at 6 months after SCI. Conclusion The decrease of miRNA-429 can increase E2F3 protein after SCI, resulting in a high risk of tumorigenesis.