中文摘要：

目的研究中波段紫外线（UVB）损伤时,p53对MEF细胞的miR-465表达的影响。方法实验采用野生型小鼠胚胎成纤维细胞（MEFp53＋/＋）和p53缺失的小鼠胚胎成纤维细胞（MEFp53-/-）,首先分别验证了这两株细胞的p53蛋白表达的差异;其次分别观察了这两种细胞在50 J/m2的UVB照射后孵育不同时间细胞存活率的改变及miR-465差异表达的情况。结果 MEFp53-/-的p53表达水平呈缺失状态;经50 J/m2UVB照射后,两种细胞的存活率均在照后2 h出现显著降低,至照后24 h未见明显恢复,且MEFp53-/-的存活率在照后多个时间点低于MEFp53＋/＋细胞;MEFp53＋/＋中miR-465的表达下调而MEFp53-/-中miR-465的表达则上调,在照后2、4、6和12 h升高均超过2倍。结论 UVB照射能引起MEF细胞存活率下降,且MEFp53-/-的存活率在多个时间点低于MEFp53＋/＋;p53基因对UVB照射后miR-465的表达具有负向调节作用。

英文摘要：

Objective To study the effects of p53 on the expression of miR - 465 in MEF cells after UVB irradia- tion. Methods Two cell lines, MEF^p53＋/＋ andMEF^p53-/- , were applied for experiment. The gene and protein expres- sion of p53 was assessed, with subsequent observation of the survival rate and the expression of miR -465 after UVB irra- diation in 50 J/m2. Results Successful p53 silence was constructed in MEF^p53 -/-. The survival rates in both cell lines were remarkably reduced since 2 hours after UVB irradiation, with no recovery 24 hours after irradiation. Significant lower cell survival was observed in MEF^p53 -/- than that inMEF^p53 ＋/＋ in most experiment time points, miR- 465 was down- regulated in MEF^p53 ＋/＋ at different time points after UVB irradiation, while it was up -regulated inMEF^p53 -/- at the cor- responding time points. Conclusion UVB radiation can cause MEF cell viability impairment, which is more prominent in MEF^p53 -/- , suggesting that P53 may play a negative regulation role in the miR -465 expression after UVB irradiation.