Insulin deficiency induces rat renal mesangial cell dysfunction via activation of IGF-1/IGF-1R pathway
Insulin deficiency induces rat renal mesangial cell dysfunction via activation of IGF-1/IGF-1R pathway
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胰岛素缺乏通过激活 IGF-1/IGF-1R 通路诱导大鼠肾系膜细胞功能障碍
DOI：
10.1038/aps.2015.128
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发表时间：
2016-02-01
影响因子：
8.2
通讯作者：
Lu, Li-min
中科院分区：
文献类型：
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作者：
Kong, Ya-li;Shen, Yang;Lu, Li-min
目的：糖尿病肾病是糖尿病的主要并发症之一，也是终末期肾病的主要原因。本研究观察了胰岛素缺乏（insulin deficiency，ID）对大鼠肾小球系膜细胞（mesangial cell，MC）及糖尿病大鼠肾脏MC的影响。用BrdU掺入法检测细胞增殖。Western blot分析胰岛素受体（IR）、胰岛素样生长因子-1受体（IGF-1 R）、磷酸化IGF-1 R、纤连蛋白和IV型胶原的表达。用IGF-1 R拮抗剂苦鬼臼脂素（PPP，20 mg· kg-1· d-1，po）治疗STZ诱导的糖尿病大鼠8周。对大鼠实施安乐死后，收集血浆和肾脏。采用RT-PCR或ELISA法检测肾皮质IGF-1水平。结果：ID培养液可明显促进肾MC增殖，增加纤维连接蛋白和IV型胶原的合成，增加IGF-1和IGF-1 R及磷酸化IGF-1 R的表达。PPP（50 nmol/L）预处理的细胞阻断ID诱导的细胞增殖和纤维连接蛋白和IV型胶原的合成增加; IGF-1 R的敲低表现出与PPP相似的效果。相反，用IGF-1（50 ng/mL）处理细胞加剧了ID诱导的细胞增殖增加。糖尿病大鼠肾脏IGF-1、IGF-1 R及磷酸化IGF-1 R表达均明显升高。结论：胰岛素缺乏可使糖尿病大鼠肾脏及肾脏MC中IGF-1和IGF-1 R的表达增加，从而促进糖尿病肾病的发生发展。
Aim:Diabetic nephropathy is one of the major complications of diabetes and the major cause of end-stage renal disease. In this study we investigated the insulin deficiency (ID) induced changes in renal mesangial cells (MCs) and in the kidney of STZ-induced diabetic rats.Methods:Cultured rat renal MCs were incubated in ID media. Cell proliferation was analyzed using BrdU incorporation assay. The expression of insulin receptor (IR), insulin-like growth factor-1 receptor (IGF-1R), phosphorylated IGF-1R, fibronectin, and collagen IV was determined with Western blot analysis. STZ-induced diabetic rats were treated with an IGF-1R antagonist picropodophyllin (PPP, 20 mg· kg− 1· d− 1, po) for 8 weeks. After the rats were euthanized, plasma and kidneys were collected. IGF-1 levels in renal cortex were measured with RT-PCR or ELISA. The morphological changes in the kidneys were also examined.Results:Incubation in ID media significantly increased cell proliferation, the synthesis of fibronectin and collagen IV, and the expression of IGF-1 and IGF-1R and phosphorylated IGF-1R in renal MCs. Pretreatment of the cells with PPP (50 nmol/L) blocked ID-induced increases in cell proliferation and the synthesis of fibronectin and collagen IV; knockdown of IGF-1R showed a similar effect as PPP did. In contrast, treatment of the cells with IGF-1 (50 ng/mL) exacerbated ID-induced increases in cell proliferation. In the kidneys of diabetic rats, the expression of IGF-1, IGF-1R and phosphorylated IGF-1R were significantly elevated. Treatment of diabetic rats with PPP did not lower the blood glucose levels, but significantly suppressed the expression of TGF-β, fibronectin and collagen IV in the kidneys, the plasma levels of urinary nitrogen and creatinine, and the urinary protein excretion.Conclusion:Insulin deficiency increases the expression of IGF-1 and IGF-1R in renal MCs and the kidney of diabetic rats, which contributes to the development of diabetic nephropathy.