PPAR-γ配体降低^(137)Cs照射诱导的PAI-1高表达

PPAR-γ ligand in suppressing radiation induced PAI-1 upregulation

目的观察大鼠肾小球膜细胞137Cs照后PAI1基因的表达情况,以及PPARγ配体Pioglitazone对照射诱导的PAI1表达的影响。方法10Gyγ线照射±10mmol/LPioglitazone处理大鼠肾小球膜细胞,用RTPCR方法证明PPARγ基因表达,用Northernblot、Westernblot方法观察PAI1基因表达,用Gelshift方法观察AP1基因的活性变化(由于PAI1基因启动子区存在AP1结合位点,加之AP1介导某些炎性因子的产生且AP1是照射诱导的早期表达基因之一,因此观察照射在大鼠肾小球膜细胞能否诱导AP1活性的升高,并进一步观察Pioglitazone对照后AP1活性的影响)。结果RTPCR方法证明了大鼠肾小球膜细胞表达PPARγ基因。10Gy照后Northernblot结果显示照后24hPAI1mRNA的表达增加,不同剂量照后24hPAI1mRNA的高表达呈照射剂量依赖性。10mmol/LPioglitazone+10Gy照后24h的Northernblot和48h的Westernblot结果表明,Pioglitazone使照射诱导的PAI1基因高表达在mRNA水平和蛋白水平均明显降低。Gelshift结果发现放疗后2hAP1活性开始升高,4h最高,加入Pioglitazone后明显被抑制。结论PPARγ配体Pioglitazone使照射诱导的肾小球膜细胞PAI1基因高表达降低,其机制可能是通过降低AP1活性来调节PAI1的表达。Pioglitazone可能具有预防或降低放射性肾损伤的作用,这将有待于动物实验的进一步证实。

Objective observe the post-radiation expression of rat mesangial cell plasminogen activator inhibitor-1 (PAI-1), and the effect of PPAR-γ ligand on radiation induced PAI-1 expression. Methods After 10?Gy γ-ray radiation of cultured rat kidney mesangial cell, RT-PCR was used to observe PPAR-γexpression. PAI-1 expression after 10?Gy radiation ±10?mmol/L pioglitazone (one of PPAR-γ ligands) was measured by Northern blot and Western blot. Gel-shift method was used to study the effect of AP-1 of PPAR-γ ligand on radiation induced PAI-1 expression. Methods Rat kidney mesangial cell expressed PPAR--γ mRNA. PAI-1 over-expressed at 24 hour after 10?Gy radiation in a radiation dose dependent manner, but not at other time. When the cell was treated with 10?Gy + 10?mmol/L pioglitazone, PAI-1 upregulation was blunted at message and protein level. AP-1 activation was increased from the 2nd hour after 10?Gy radiation and reached the highest level at the 4th hour. When pioglitazone was added, the radiation induced increase in AP-1 activation was suppressed at the 4th hour. Conclusions Pioglitazone, mediated by AP-1 gene, can suppress radiation induced PAI-1 upregulation.