抗肾小球基底膜抗体诱导的新月体性肾小球肾炎大鼠肾小球中I型胶原蛋白细胞来源的鉴定

Identification of cellular origin of type I collagen in glomeruli of rats with crescentic glomerulonephritis induced by anti-glomerular basement membrane antibody.

作者信息

He J S, Hayashi K, Horikoshi S, Funabiki K, Shirato I, Tomino Y

机构信息

Division of Nephrology, Department of Medicine, Juntendo University School of Medicine, Tokyo, Japan.

出版信息

Nephrol Dial Transplant. 2001 Apr;16(4):704-11. doi: 10.1093/ndt/16.4.704.

DOI:10.1093/ndt/16.4.704

PMID:11274263

Abstract

BACKGROUND

Type I collagen is an interstitial collagen, which is not present in normal glomeruli. As type I collagen was observed in advanced glomerular lesions, it appears to be associated with deterioration of renal function. However, the origins of cells expressing type I collagen mRNA in glomeruli of diseased kidneys remains controversial.

METHODS

We examined the expression of type I collagen in glomeruli at protein and mRNA levels in rat crescentic glomerulonephritis induced by anti-glomerular basement membrane (GBM) antibody. In addition, in situ hybridization and immunohistochemical staining of serial sections were performed to identify the cellular origin of type I collagen in glomeruli.

RESULTS

Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) in isolated glomeruli showed that mRNA expression of type I collagen was remarkably increased on days 7, 14, and 28 after anti-GBM antibody injection (12.2+/-1.4, 20.2+/-2.1 and 14.6+/-1.0-fold over day 0, respectively). Immunofluorescence for type I collagen demonstrated marked staining in the fibrocellular and fibrous crescents, and weak staining within glomerular mesangial areas. In close association with mRNA levels analysed by RT-PCR, in situ hybridization revealed predominant presence of alpha1(I) collagen mRNA in cells within crescentic areas and Bowman's capsules. Serial section analysis for immunostaining and in situ hybridization showed that some alpha1(I) collagen mRNA-positive cells were also positive for cytokeratin. In contrast, no alpha1(I) collagen mRNA-positive cells were stained by ED-1 and podocalyxin.

CONCLUSIONS

It appears that increased expression of type I collagen at the protein and mRNA levels in glomeruli is involved in the progression of glomerulonephritis. At least in this crescentic model, parietal epithelial cells (PECs) may partially contribute to the dysregulated production of type I collagen, which leads to glomerulosclerosis.

摘要

背景

I型胶原蛋白是一种间质胶原蛋白，在正常肾小球中不存在。由于在晚期肾小球病变中观察到I型胶原蛋白，它似乎与肾功能恶化有关。然而，患病肾脏肾小球中表达I型胶原蛋白mRNA的细胞来源仍存在争议。

方法

我们在抗肾小球基底膜（GBM）抗体诱导的大鼠新月体性肾小球肾炎中，在蛋白质和mRNA水平上检测了肾小球中I型胶原蛋白的表达。此外，对连续切片进行原位杂交和免疫组织化学染色，以确定肾小球中I型胶原蛋白的细胞来源。

结果

分离的肾小球中的半定量逆转录-聚合酶链反应（RT-PCR）显示，抗GBM抗体注射后第7天、14天和28天，I型胶原蛋白的mRNA表达显著增加（分别比第0天高12.2±1.4、20.2±2.1和14.6±1.0倍）。I型胶原蛋白的免疫荧光显示在纤维细胞性和纤维性新月体中有明显染色，在肾小球系膜区域内染色较弱。与RT-PCR分析的mRNA水平密切相关，原位杂交显示α1（I）胶原蛋白mRNA主要存在于新月体区域和鲍曼囊内的细胞中。免疫染色和原位杂交的连续切片分析表明，一些α1（I）胶原蛋白mRNA阳性细胞也对角蛋白呈阳性。相反，没有α1（I）胶原蛋白mRNA阳性细胞被ED-1和足细胞标记蛋白染色。