目的：探讨miR-486-5P对裸鼠皮下人胃癌移植瘤生长的影响及其可能的作用机制。方法：建立胃癌SGC-7901细胞裸鼠皮下移植瘤模型,经miR-486-5P过表达质粒处理后,观察裸鼠皮下移植瘤生长情况，采用Western blotting及免疫组织化学法检测miR-486-5p靶基因神经纤毛蛋白-2（NRP2）的表达水平。结果：成功构建胃癌SGC-7901细胞裸鼠皮下移植瘤模型；实验组移植瘤内miR-486-5p的表达水平明显高于对照组（P<0.05)，miR-486-5p可明显抑制裸鼠皮下胃癌移植瘤的生长；与阴性及空白对照组相比，实验组平均瘤体质量明显下降\[(0.404±0.080) vs (0.748±0.122)、（0.788±0.176）g，均P＜0.05\]；移植瘤平均体积明显减小\[(0.333±0.039) vs (0.597±0.175)、(0.594±0.216）cm3，均P＜0.05\]，实验组的抑瘤率达46.99 %；实验组经miR-486-5p过表达质粒处理后，免疫组化检测结果显示，NRP2蛋白主要定位于胃癌细胞质内，呈棕黄色颗粒；实验组NRP2蛋白的IHS得分显著低于阴性及空白对照组\[（2.2±0.84） vs （6.4±0.89）,（6.2±1.48），均P<001\]；阴性对照组与空白对照组的得分差异无统计学意义（P>0.05）；Western blotting检测结果显示，实验组移植瘤组织中NRP2蛋白的相对表达量显著低于阴性及空白对照组\[（0.04±0.006） vs （0.70±0.03）,（0.68±0.02），P<0.01\]。阴性和空白对照组间的IHS得分值、抑瘤率及NRP2蛋白表达水平的差异均无统计学意义（P>0.05）。结论：miR-486-5p可明显抑制裸鼠皮下胃癌SGC-7901细胞移植瘤的生长，其作用机制可能与抑制NRP2的表达有关。

Objective:To explore the effect of miR-486-5p on gastric cancer xenograft in nude mice and to investigate its probable mechanism. Methods: The subcutaneously transplanted tumor models of human gastric carcinoma (SGC-7901 cell line) in nude mice were established and after treated with miR-486-5p over-expression plasmids, growth situation of cancer xenografts in the nude mice was observed. The expression of NRP2（the target gene of miR-486-5p）were detected by Western blotting and immunohistochemical method. Results：Gastric carcinoma (SGC-7901) xenograft models in nude mice were successfully constructed; miR-486-5p can significantly inhibit the growth of xenografts in nude mice and the expression of miR-486-5p in cancer xenografts of experimental group was significantly higher than that of control group (P＜0.05). Compared to the negative control group and blank control group, the average mass and volume of cancer xenografts in experiment group was significantly less than those in the other groups, mass:(0.404±0.080) g vs (0.748±0.122) g, (0.788±0.176) g, all P＜0.05; volume: (0.333±0.039) cm3 vs (0.597±0.175) cm3, (0.594±0.216) cm3, P＜005, and the inhibition rate of cancer xenografts in experiment group was 46.99%. After treated with miR-486-5p over-expression plasmid in experiment group, the immunohistochemical results showed that NRP2 protein, presenting as yellow particle, mainly existed in the cytoplasm of gastric cancer cells; the IHS score of NRP2 protein in miR-486-5p group was significantly lower than that of NC and blank control groups (\[2.2±0.84\] vs \[6.4±0.89\], \[6.2±1.48\], all P<001); however, there was no significant difference between negative control and blank control groups (P＞005). The results of Western blotting shown that the relative expression of NRP2 protein in cancer xenograft tissues of experiment group was significantly less than that of the other groups (\[0.04±0.006\] vs \[0.70±0.03\], (0.68±002\]，all P<001). The difference in IHS score, inhibition rate of cancer and NRP2 protein expression between NC and blank control groups had no statistical significance (P>0.05). Conclusion: miR-486-5p can remarkably inhibit the growth of gastric cancer xenograft in nude mice. It may associate with inhibiting expression of NRP2.

山东省自然科学基金资助项目（No. ZR2014HQ072）；山东省医药卫生科技发展计划资助项目（No. 2014WS0490）；滨州市科技发展计划资助项目（No. 2014ZC0116）