PAI-1和TIMP-1基因在肾小管间质纤维化中的表达及HGF的干预作用

目的:研究纤溶酶原激活物抑制剂1(PAI-1)和组织基质金属蛋白酶抑制剂1(TIMP-1)基因表达与梗阻性肾病小管间质纤维化(TIF)进展的关系及肝细胞生长因子(HGF)的干预作用。方法: 60只Wistar大鼠随机分为4组:正常大鼠组、假手术组、单侧输尿管梗阻组和HGF治疗组,分别于模型3 d、7 d、14 d、21 d处死大鼠。采用逆转录多聚酶链反应(RT-PCR)检测PAI-1和TIMP-1 mRNA表达水平;底物酶谱法检测肾脏MMP2、9活性的变化,测定肾组织羟脯氨酸含量判断纤维化程度。结果:梗阻肾组织PAI-1和TIMP-1 mRNA表达显著高于对照组,并伴有明显的梗阻肾MMP2,MMP9活性低于和羟脯氨酸含量高于对照组,而21 d HGF治疗组PAI-1和TIMP-1 mRNA表达明显下调,MMP2,MMP9活性高于和肾组织羟脯氨酸含量少于对照组。结论: PAI-1、TIMP-1 mRNA表达增高是小管间质ECM降解减少的主要原因之一,也是造成TIF加重的重要因素,而HGF可拮抗这一进程,减轻小管间质纤维化。

PAI- 1, TIMP- 1 gene expression in renal tubulointerstitial fibrosis of ureteral obstruction and the interfering effects of HGF treatment

AIM: The aim of this study was to determine the relationship between PAI-1,TIMP-1 gene expression and renal tubulointerstitial fibrosis(TIF) of ureteral obstruction ,and the interfering effects of hepatocyte growth factor (HGF) treatment. METHODS: Sixty rats were divided into normal control, sham operation,unilateral ureteral obstruction(UUO),and rhHGF treated groups (received 0.5 mg·kg^-1·d^-1 HGF for twenty-one days), and were sacrificed at postoperative day 3, 7, 14, 21. The levels of PAI-1, TIMP-1 mRNA were measured by RT-PCR. MMP2 and MMP9 activities were detected by substrate zymography, and renal fibrosis was assessed by measuring tissue hydroxyproline. RESULTS: Compared to controls, expression levels of PAI-1,TIMP-1 mRNA were significantly increased in UUO rats, and this was accompanied by decreased activities of MMP2 and MMP9 and increase in tissue hydroxyproline content. HGF treatment significantly decreased expressions of PAI-1, TIMP-1 mRNA, increased MMP2 and MMP9 activities,and decreased tissue hydroxyproline content in the obstructive kidney. CONCLUSIONS: These results indicate that the increases in PAI-1, TIMP-1 mRNA expression may be the major cause of sustained decreased matrix degradation during the development of tubulointerstitial fibrosis after unilateral ureteral obstruction. rhHGF efficiently ameliorates renal tubulointerstitial injury by the reduction of PAI-1,TIMP-1 mRNA expression, and increasing MMP2, MMP9 activities.