肾上腺髓质素在单侧输尿管梗阻大鼠中通过抑制氧化应激而上调并减轻肾纤维化。

Intermedin is upregulated and attenuates renal fibrosis by inhibition of oxidative stress in rats with unilateral ureteral obstruction.

作者信息

Qiao Xi, Wang Lihua, Wang Yanhong, Zhao Ning, Zhang Ruijing, Han Weixia, Peng Zhiqiang

机构信息

Department of Nephrology, Second Hospital of Shanxi Medical University, Taiyuan, Shanxi, China.

Shanxi Kidney Disease Institute, Shanxi Medical University, Taiyuan, Shanxi, China.

出版信息

Nephrology (Carlton). 2015 Nov;20(11):820-31. doi: 10.1111/nep.12520.

DOI:10.1111/nep.12520

PMID:26014968

Abstract

AIM

Transforming growth factor-β1 (TGF-β1) plays a pivotal role in the progression of renal fibrosis. Reactive oxygen species mediate profibrotic action of TGF-β1. Intermedin (IMD) has been shown to inhibit oxidative stress, but its role in renal fibrosis remains unclear. Here, we investigated the effects of IMD on renal fibrosis in a rat model of unilateral ureteral obstruction (UUO).

METHODS

The expression of IMD and its receptors, calcitonin receptor-like receptor (CRLR) and receptor activity-modifying proteins (RAMP1/2/3), in the obstructed kidney was detected by real-time polymerase chain reaction (PCR), western blotting and immunohistochemistry. To evaluate the effects of IMD on renal fibrosis, we locally overexpressed exogenous IMD in the obstructed kidney using an ultrasound-microbubble-mediated delivery system. Renal fibrosis was determined by Masson trichrome staining. The expression of TGF-β1, connective tissue growth factor (CTGF), α-smooth muscle actin (α-SMA) and fibronectin was measured. Smad2/3 activation and macrophage infiltration were evaluated. We also studied oxidative stress by measuring superoxide dismutase (SOD) activity and malondialdehyde (MDA) content.

RESULTS

mRNA and protein expression of IMD increased after UUO. CRLR, RAMP1, RAMP2 and RAMP3 were also induced by ureteral obstruction. IMD overexpression remarkably attenuated UUO-induced tubular injury and blunted fibrotic response as shown by decreased interstitial collagen deposition and downregulation of fibronectin. Macrophage infiltration, α-SMA and CTGF upregulation caused by UUO were all relieved by IMD, whereas TGF-β1 upregulation and Smad2/3 activation were not affected. Meanwhile, we noted increased oxidative stress in obstruction, which was also attenuated by IMD gene delivery.

CONCLUSIONS

Our results indicate that IMD is upregulated after UUO. IMD plays a protective role in renal fibrosis via its antioxidant effects.

摘要

目的

转化生长因子-β1（TGF-β1）在肾纤维化进展中起关键作用。活性氧介导TGF-β1的促纤维化作用。中介素（IMD）已被证明可抑制氧化应激，但其在肾纤维化中的作用仍不清楚。在此，我们在单侧输尿管梗阻（UUO）大鼠模型中研究了IMD对肾纤维化的影响。

方法

通过实时聚合酶链反应（PCR）、蛋白质印迹法和免疫组织化学检测梗阻肾脏中IMD及其受体降钙素受体样受体（CRLR）和受体活性修饰蛋白（RAMP1/2/3）的表达。为了评估IMD对肾纤维化的影响，我们使用超声微泡介导的递送系统在梗阻肾脏中局部过表达外源性IMD。通过Masson三色染色确定肾纤维化。检测TGF-β1、结缔组织生长因子（CTGF）、α-平滑肌肌动蛋白（α-SMA）和纤连蛋白的表达。评估Smad2/3激活和巨噬细胞浸润。我们还通过测量超氧化物歧化酶（SOD）活性和丙二醛（MDA）含量来研究氧化应激。

结果

UUO后IMD的mRNA和蛋白表达增加。输尿管梗阻也诱导了CRLR、RAMP1、RAMP2和RAMP3。IMD过表达显著减轻了UUO诱导的肾小管损伤，并减弱了纤维化反应，表现为间质胶原沉积减少和纤连蛋白下调。IMD缓解了UUO引起的巨噬细胞浸润、α-SMA和CTGF上调，而TGF-β1上调和Smad2/3激活未受影响。同时，我们注意到梗阻时氧化应激增加，IMD基因递送也使其减弱。