NDT Advance Access originally published online on September 22, 2004
Nephrology Dialysis Transplantation 2004 19(12):2981-2986; doi:10.1093/ndt/gfh489
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Nephrol Dial Transplant Vol. 19 No. 12 © ERA-EDTA 2004; all rights reserved
Original Article
Ultrastructural study on nephrin expression in experimental puromycin aminonucleoside nephrosis
1 Division of Nephrology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 2 Clinical Research Center, Samsung Biomedical Research Institute, Seoul, Korea and 3 Institute of Nephrology, Niigata University School of Medicine, Japan
Correspondence and offprint request to: Dae Joong Kim, MD, Division of Nephrology, Samsung Medical Center, 50 Ilwondong, Kangnamgoo, Seoul, Korea 135-710. E-mail: kimdjmed{at}hanmail.net
Background. Nephrin is a recently identified protein that is a key component of the slit diaphragm. This protein may play a crucial role in maintaining the glomerular filtration barrier, and mutations in the gene for nephrin reportedly lead to congenital nephrosis. However, the expression of nephrin in acquired glomerular disease has not yet been fully clarified. To address this issue, we analysed the expression and localization of nephrin by morphological analysis based on immunoelectron microscopy in normal glomeruli and in glomeruli from proteinuric experimental models.
Methods. Twenty rats were divided into three experimental groups (n = 16 total) and a control group (n = 4). Rats in the experimental groups received a single intravenous injection of puromycin aminonucleoside (PAN), and were sacrificed at 1 (n = 4), 2 (n = 6) and 3 weeks (n = 6) post-injection. Nephrin expression was assessed by immunoelectron microscopy using a polyclonal antibody against nephrin and gold particles. It was quantified by counting the gold particles and the slit diaphragms and by measuring the average foot process width in microphotographs.
Results. The average foot process width in the 1 week group (5924.5±1523.9 nm) was far greater than that of controls (1112.9±79.8 nm), but decreased thereafter. The average number of total gold particles per unit length (10 000 nm) of the glomerular basement membrane (GBM) underlying the foot processes was reduced at 1 week (26.0±9.5), compared with controls (335.3±125.5), but increased thereafter. Also, the average number of junctional gold particles per unit length of the GBM was lower than controls (208.4±1.7) at 1 week (10.1±3.5), but increased thereafter. There were no significant differences between the numbers of junctional gold particles per slit diaphragm among the groups, but significant differences were observed in the distributions of gold particles among the groups. Gold particles were more frequently seen in cytoplasm at 1 week.
Conclusions. The present ultrastructural studies showed that nephrin expression and its distribution were altered in PAN-treated rats, and this occurred in parallel with foot process effacement. Nephrin expression returned to normal with improved resolution of the effacement. Nephrin expression was found to be rather preserved in areas without foot process effacement, even in PAN-treated rats. The significance of the above findings in terms of proteinuria and foot process effacement needs further clarification.
Keywords: nephrin; proteinuria; puromycin aminonucleoside
*Young Ki Lee and Taegun Kwon contributed equally to this work.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  M. Nagase, S. Shibata, S. Yoshida, T. Nagase, T. Gotoda, and T. Fujita Podocyte Injury Underlies the Glomerulopathy of Dahl Salt-Hypertensive Rats and Is Reversed by Aldosterone Blocker Hypertension, June 1, 2006; 47(6): 1084 - 1093. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Xing, J. Ding, Q. Fan, and N. Guan Diversities of Podocyte Molecular Changes Induced by Different Antiproteinuria Drugs. Experimental Biology and Medicine, May 1, 2006; 231(5): 585 - 593. [Abstract] [Full Text] [PDF]
|
|