背景:目前尚未见脂肪间质干细胞体外诱导分化成多巴胺能神经元的报道,且有关脂肪间质干细胞维持多巴胺能神经元存活的机制也缺乏实验证据。目的:观察腺病毒介导胶质细胞系源性神经营养因子基因修饰的脂肪间质干细胞对共培养条件下多巴胺能神经元存活的影响。设计、时间及地点:细胞学体外对比观察,于2007-03/12在吉林省耳鼻咽喉研究所和教育部吉林大学人兽共患病重点实验室完成。材料:3周龄Wistar大鼠、孕14 d Wistar大鼠由吉林大学白求恩医学院实验动物中心提供。方法:采用pAdTrackCV和pAdEasy-1系统构建重组胶质细胞系源性神经营养因子腺病毒。取孕14d大鼠,采用酶消化法培养中脑多巴胺能神经元。取Wistar大鼠腹股沟处脂肪,酶消化法分离培养脂肪间质干细胞,体外培养至第3代当细胞生长至60%融合时,以病毒滴度为1×109vp/mL的胶质细胞系源性神经营养因子重组腺病毒作用细胞1h后,转移到生长培养基继续培养,通过ELISA法检测培养上清胶质细胞系源性神经营养因子水平。设立3组:Ad-GDNF转染共培养组、Ad-GFP转染共培养组分别在脂肪间质干细胞经相应病毒转染24h后加入分离的多巴胺能神经元,继续培养7d;单纯多巴胺能神经元培养组不加入脂肪间质干细胞。主要观察指标:采用免疫荧光技术检测共培养环境对多巴胺能神经元存活的影响,共培养环境对胶质细胞系源性神经营养因子修饰脂肪间质干细胞分化的影响。结果:脂肪间质干细胞在pAd-GDNF转染24h后细胞上清中出现胶质细胞系源性神经营养因子蛋白,72h达高峰,pAd-GDNF对脂肪间质干细胞的转染效率约为80%。酪氨酸羟化酶免疫荧光染色结果发现,Ad-GDNF转染共培养组多巴胺能神经元存活率明显高于单纯多巴胺能神经元培养组、Ad-GFP转染共培养组(55%,15%,25%,P<0.01)。对共培养7d的细胞进行酪氨酸羟化酶免疫荧
Objective To construct recombinant lentiviral vectors for gene delivery of the glial cell line-derived neurotropnic factor （GDNF）, and evaluate the neuroprotective effect of GDNF on lactacystin-damaged PC12 cells by transfecting it into bone marrow stromal cells （BMSCs）. Methods pLenti6/V5-GDNF plasmid was set up by double restriction enzyme digestion and ligation, and then the plasmid was transformed into Top10 cells. Purified pLenti6/V5-GDNF plasmids from the positive clones and the packaging mixture were cotransfected to the 293FT packaging cell line by Lipofectamine2000 to produce lentivirus, then the concentrated virus was transduced to BMSCs. Overexpression of GDNF in BMSCs was tested by RT-PCR, ELISA and immunocytochemistry, and its neuroprotection for lactacystin-damaged PC12 cells was evaluated by MTT assay. Results Virus stock of GDNF was harvested with the titer of 5.6×10^5 TU/mL. After tmnsduction, GDNF-BMSCs successfully secreted GDNF to supematant with nigher concentration （800 pg/mL） than BMSCs did （less than 100 pg/mL）. The supematant of GDNF-BMSCs could significantly alleviate the damage of PC12 cells induced by lactacystin （10 μmol/L）. Conclusion Overexpression of lentivirus-mediated GDNF in the BMSCs cells can effectively protect PC12 cells from the injury by the proteasome inhibitor.
