西罗莫司对大鼠肾间质纤维化的防治作用及机制研究

Preventive effect and mechanism of Sirolimus on renal interstitial fibrosis in rats

目的:研究西罗莫司(Sir)对单侧输尿管梗阻大鼠模型肾间质纤维化的作用及机制,为临床使用提供依据。方法:选取雄性SD大鼠36只,随机分为3组(n=12):模型组(UUO组)、假手术组(Sham组)、西罗莫司治疗组(Sir组)。对UUO组和Sir组采用单侧输尿管结扎建立大鼠肾纤维化模型,治疗组每日给予西罗莫司2mg/kg灌胃。分别于第7、14天取大鼠梗阻侧肾脏。HE染色观察肾组织病理变化,免疫组化法检测大鼠肾组织TGF-β1的表达;RT-PCR检测TGF-β1 mRNA的表达;Western blot检测TβR-Ⅰ和α-SMA蛋白的表达。结果:Sham组未显示肾纤维化,UUO组显示大鼠肾间质纤维化及炎症细胞浸润,Sir组病变程度均较UUO组减轻。7d和14d UUO组大鼠肾组织TGF-β1阳性细胞数及TGF-β1 mRNA表达水平均较Sham组明显增高(P<0.05);7d和14d Sir组肾组织TGF-β1阳性细胞数及TGF-β1 mRNA表达水平均较同时间点UUO组下降(P<0.05)。Western blot检测发现与Sham组相比,UUO组大鼠肾组织TβR-Ⅰ、α-SMA表达增加(P<0.05),Sir组大鼠肾组织TβR-Ⅰ、α-SMA表达较UUO组降低(P<0.05)。结论:西罗莫司治疗可减轻UUO大鼠肾间质纤维化,其机制可能与抑制TGF-β1-Smad信号通路有关。

Objective: To study the effect and mechanism of Sirolimus on renal interstitial fibrosis in a rat model of unilateral ureteral obstruction,and provide evidence for clinical use. Methods: Thirty-six male SD rats were randomly divided into 3 groups( n =12):model group(UUO group),Sham operation group(Sham group),and Sirolimus treatment group(Sir group).Unilateral ureteral ligation was used to establish renal fibrosis model in UUO group and Sir group.The treatment group was given gastric lavage with Sirolimus 2 mg/kg daily.Rats′ obstructed lateral kidneys were taken on the 7th and 14th day respectively.HE staining was used to observe the pathological changes of renal tissues.Immunohistochemical method was used to detect the expression of TGF-β1 in rat renal tissues.RT-PCR was used to detect the expression of TGF-β1 mRNA.Western blot was used to detect the expression levels of TβR-Ⅰ and α-SMA proteins. Results: The Sham group did not show renal fibrosis.The UUO group showed renal interstitial fibrosis and inflammatory cell infiltration.The Sir group showed less lesions than the UUO group.The number of TGF-β1 positive cells and the expression of TGF-β1 mRNA in the kidneys of the UUO group rats were significantly higher than those in the Sham group on the 7th and 14th day( P <0.05).The number of TGF-β1 positive cells and the expression of TGF-β1 mRNA decreased compared with the UUO group on the 7th and 14th day( P <0.05).Western blot showed that compared with the Sham group the expression of TβR-Ⅰ and α-SMA in the kidneys of the UUO group increased ( P <0.05),and the expression of TβR-I and α-SMA in the kidney of the Sir group was lower than that in UUO group( P <0.05). Conclusion: Sirolimus treatment can reduce renal interstitial fibrosis in UUO rats,and its mechanism may be related to inhibition of TGF-β1-Smad signaling pathway.