超声造影剂及超声辐照对TIMP-1 siRNA在肝纤维化大鼠肝组织中表达的影响

目的观测超声造影剂及超声辐照对TIMP-1 siRNA质粒转染肝纤维化大鼠肝组织内TIMP-1基因表达的影响。方法采用二甲基亚硝胺（DMN）方法建立大鼠肝纤维化模型，72只造模大鼠在第6周随机均分成3组，质粒组（P组）、质粒＋造影剂及超声照射组（P＋U组）、对照组。2d、6d及12d后各组分别随机取8只处死、取肝、肾、肺、脑、心肌组织快速冷冻切片，荧光显微镜下观察各组织内TIMP-1 siRNA荧光表达；FQ—PCR测定肝组织TIMP-1 mRNA表达。结果2d后，P组肝、肾、肺、脑、心肌组织内均有少量TIMP-1 siRNA绿色荧光表达，组间无显著差异，P＞0．05；P＋U组肝组织内TIMP-1 siRNA荧光表达明显增强，较其它组织差异显著，P＜0．001。P组及P＋U组肝组织TIMP-1 mRNA表达量均较对照组明显降低，P＜0．001；P＋U组降低较P组显著，P＜0．001；P＋U组6d时TIMP-1 mRNA表达量最低，后依次为48h、12d。结论TIMP-1 siRNA对肝纤维化大鼠TIMP-1基因表达抑制作用明显；超声造影剂及超声辐照能够明显增高基因转染效率，并有将基因载体靶向定位于肝组织释放的作用。

Effect of Ultrasound Contrast Agent and Ultrasound Irradiation on TIMP-1 siRNA Expression in Hepatic Fibrosis in Rat Liver

Objective To investigate the effect of ultrasound contrast agent and ultrasound irradiation on TIMP-1 siRNA expression in liver of hepatic fibrosis rats.Methods The rat hepatic fibrosis model was established by abdominal injection of dimethylnitrosamine(DMN).A total of 72 hepatic fibrosis rats were divided into 3 groups at 6 weeks:group plasmid(group P):TIMP-1 siRNA was injected into the penial vein ;group plasmid+ultrasound contrast agent(group P+U):TIMP-1 siRNA and ultrasound contrast agent were injected into the penial vein,then were irradiated by ultrasound for 5 minutes with mechanical index(MI) 1.0;group contrast(group C):normal saline was injected into the penial vein.Fluorescent expression of TIMP-1 siRNA was observed in ice tissues pieces of liver,kidney,heart,lung and brain after 48 h,6 d and 12 d.TIMP-1 mRNA expression was detected using full quantitative RT-PCR.Results At 48 h,low level fluorescent expression was found in all tissues of group P;fluorescent expression in liver of group P+U was significantly higher than those in other groups(P<0.001).At 6 d and 12 d,fluorescent expression was not obvious in liver of both groups.TIMP-1 mRNA expression was significantly decreased in group P and group P+U than that in the group C(P<0.05);the decrease was more significant in group P+U than in group P.Conclusions TIMP-1 siRNA significantly inhibited the expression of TIMP-1 mRNA in hepatic fibrosis rats.Ultrasound contrast agent and ultrasound irradiation promoted gene transfection and targeted TIMP-1 siRNA to the liver.