水飞蓟素对肾小管间质纤维化大鼠转化生长因子-β_1 mRNA和金属蛋白酶组织抑制物-1 mRNA表达的影响

Effect of silymarin on the expression of transforming growth factor-β_1 mRNA and tissue inhibitor metalloproteinase-1 mRNA in rats with tubulointerstitial fibrosis

目的探讨水飞蓟素对肾小管间质纤维化大鼠肾脏病理、肾组织Ⅲ型胶原蛋白及转化生长因子-β1(TGF-β1)mRNA和金属蛋白酶组织抑制物-1(TIMP-1)mRNA表达的影响。方法 SD大鼠72只随机分为假手术组、模型组和治疗组,每组24只。行单侧输尿管梗阻(UUO)术诱导肾小管间质纤维化模型。治疗组大鼠给予30 mg.kg-1水飞蓟素,模型组及假手术组给予生理盐水灌胃。分别于UUO术后第7、14、21天各组随机处死8只大鼠,光镜下观察肾组织的病理改变,免疫组织化学法评价肾组织Ⅲ型胶原蛋白的表达,逆转录聚合酶链反应(RT-PCR)检测各组肾组织TGF-β1mRNA及TIMP-1 mRNA的表达水平。结果各时间点肾小管间质损伤和肾组织Ⅲ型胶原蛋白表达量在治疗组和模型组均较假手术组明显增多(P均<0.01),治疗组较模型组则明显减轻(P均<0.05)。各时间点治疗组和模型组肾脏TGF-β1mRNA和TIMP-1 mRNA表达量明显高于假手术组(P均<0.01),治疗组则明显低于模型组(P均<0.05)。UUO大鼠肾间质中TGF-β1mRNA、TIMP-1 mRNA表达量与肾小管间质损伤评分均呈正相关(r=0.915、0.838、P均<0.01)。TGF-β1mRNA、TIMP-1 mRNA表达量与肾组织Ⅲ型胶原蛋白表达量均呈正相关(r=0.833、0.786、P均<0.01)。结论在UUO大鼠模型中,水飞蓟素通过下调TGF-β1mRNA、TIMP-1 mRNA的表达,减少Ⅲ型胶原的产生,从而发挥延缓肾间质纤维化的作用。

Objective To investigate the effect of silymarin on renal pathological change and the expression of type Ⅲ collagen,transforming growth factor-β1（TGF-β1） mRNA and tissue inhibitor metalloproteinase-1（TIMP-1） mRNA in rats with tubulointerstitial fibrosis.Methods Seventy-two Sprague-Dawley rats were randomly divided into sham-operated group,model group and silymarin treated group,and 24 rats in each group.Renal tubulointerstitial fibrosis model was established by unilateral ureteral obstruction（UUO）.Rats in silymarin treated group were received administration of silymarin（30 mg·kg-1 per day by gavage）,and normal saline was given to the rats in model group and sham-operated group at the same time.In each group,eight rats were killed at the 7th,14th and 21st day after operation.Histological changes of tubulointerstitial injury were observed under microscope.The expression of type Ⅲ collagen was detected by immunohistochemical method,and TGF-β1 mRNA and TIMP-1 mRNA in renal tissue were determined with reverse transcription polymerase chain reaction（RT-PCR） method.Results The degree of renal tubulointerstitial injury and the expression of type Ⅲ collagen in silymarin treated group and model group were increased than those of sham-operated group at the 7th,14th and 21st day after operation（P0.01）,but the indexes in silymarin treated group were lighter than those in model group（P0.05,）.Compared with sham-operated group,the expression of TGF-β1 mRNA and TIMP-1 mRNA were significantly up-regulated at the 7th,14th and 21st day after operation in silymarin treated group and model group（P0.01）,and those in silymarin treated group were significantly down-regulated than model group（P0.05）.The quantification expression of TGF-β1 mRNA and TIMP-1 mRNA showed a positive correlation with tubulointerstitial score（r=0.915,0.838,P0.01） in UUO rats.The quantification expression of TGF-β1 mRNA and TIMP-1 mRNA also indicated a positive correlation with that of type Ⅲ collagen（r=0.833,0.786,P0.05）.Conclusion These results suggest that silymarin maybe attenuate the renal tubulointerstitial fibrosis though the mechanism by the down-regulated expression of TGF-β1 mRNA and TIMP-1 mRNA and reducing the expression of type Ⅲ collagen in UUO rats.