Astragaloside IV inhibits renal tubulointerstitial fibrosis by blocking TGF-β/Smad signaling pathway in vivo and in vitro
Astragaloside IV inhibits renal tubulointerstitial fibrosis by blocking TGF-β/Smad signaling pathway in vivo and in vitro
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DOI：
10.1177/1535370214532597
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发表时间：
2014-10-01
影响因子：
3.2
通讯作者：
Cai, Hui
中科院分区：
文献类型：
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作者：
Wang, Li;Chi, Yang-Feng;Cai, Hui
黄芪甲苷（AS-IV）是黄芪的主要活性成分，被认为是一种肾脏保护剂，但其分子机制尚不清楚。因此，我们设计了研究AS-IV在单侧输尿管梗阻（UUO）诱导的大鼠肾纤维化模型中的保护作用和机制，在体内和体外TGF-β 1刺激的大鼠肾成纤维细胞（NRK-49 F）中。SD大鼠随机分为假手术组、UUO组、UUO/AS-IV组（3.3，10，33mg.kg（-1）.d（-1））和UUO/依那普利组（4mg.kg（-1）.d（-1））。检测肾功能、肾小管间质损伤指数评分、细胞外基质（ECM）沉积以及TGF-β 1、结缔组织生长因子（CTGF）、α-SMA、纤连蛋白、胶原I、III、Smad 2/3、磷酸化Smad 2/3和Smad 7的表达。此外，在TGF-β 1刺激的NRK-49 F细胞系中测量CTGF、α-SMA、纤连蛋白、胶原I、III、Smad 2/3、磷酸化Smad 2/3和Smad 7的表达。AS-IV显著降低UUO诱导的肾纤维化和功能损害，这与TGF-β 1、CTGF、α-SMA和胶原基质表达的抑制以及血清肌酐和尿素氮的降低有关。AS-IV对纤维化的肾保护作用与Smad 7的上调相关，从而阻断TGF-β 1、CTGF和α-SMA的上调以及磷酸化Smad 2/3的激活。这些作用在TGF-β 1刺激的NRK-49 F细胞系中得到进一步证实。此外，NRK-49 F细胞中Smad 7基因的敲低能够防止AS-IV诱导的对Smad 2/3信号传导激活、CTGF、α-SMA和ECM蛋白表达的抑制，以响应TGF-β 1。AS-IV治疗可减轻肾小管间质纤维化，这与Smad 7的诱导密切相关，从而抑制TGF-β/Smad信号传导。
Astragaloside IV (AS-IV) is a major active ingredient from Radix astragali, which has been considered as a renoprotective agent; however, its molecular mechanisms are unclear. Thus, we designed to investigate the renoprotective effects and mechanisms of AS-IV in rat model of renal fibrosis induced by unilateral ureteral obstruction (UUO) in vivo and TGF-beta 1-stimulated rat renal fibroblasts (NRK-49F) in vitro. Sprague-Dawley rats were randomly divided into six groups: sham operation, UUO, UUO/AS-IV (3.3, 10, 33mg.kg(-1).d(-1)), and UUO/enalapril (4mg.kg(-1).d(-1)). Renal function, tubulointerstitial damage index score, extracellular matrix (ECM) deposition, and the expressions of TGF-beta 1, connective tissue growth factor (CTGF), alpha-SMA, fibronectin, collagen I, III, Smad2/3, phosphorylated-Smad2/3, and Smad7 were measured. In addition, the expressions of CTGF, alpha-SMA, fibronectin, collagen I, III, Smad2/3, phosphorylated-Smad2/3, and Smad7 were measured in TGF-beta 1-stiumlated NRK-49F cell line. AS-IV significantly decreased UUO-induced renal fibrosis and functional impairment, which are associated with inhibition of TGF-beta 1, CTGF, alpha-SMA, and collagen matrix expression, and a decrease in serum creatinine and urea nitrogen. The renoprotective effects of AS-IV on fibrosis were associated with up-regulation of Smad7, thereby blocking up-regulations of TGF-beta 1, CTGF, and alpha-SMA, and activation of phosphorylated-Smad2/3. These effects were further conformed in NRK-49F cell line stimulated by TGF-beta 1. Moreover, knockdown of Smad7 gene in NRK-49F cells was able to prevent AS-IV-induced inhibition to Smad2/3 signaling activation, expression of CTGF, alpha-SMA, and ECM proteins in response to TGF-beta 1. Renal tubulointerstitial fibrosis was attenuated by treatment with AS-IV, which was closely related to induction of Smad7, thereby inhibiting TGF-beta/Smad signaling.