Abstract
In several models of progressive glomerular disease, mesangial cell proliferation, phenotypic change and increased growth factor expression precede up-regulation of genes for extracellular matrix components (ECM) and mesangial expansion. To examine these events in diabetic nephropathy (DN) we conducted sequential studies of glomeruli in rats with streptozotocin induced DN. We found prominent mesangial cell proliferation at three days (4.34 ± 2.24 PCNA + cells/glom vs. 1.6 ± 0.74 in controls, P < 0.001) associated with increased α-actin expression. PDGF B-chain mRNA was slightly increased at day one, and PDGF B-chain immunostaining was slightly increased at days one and six. Staining for bFGF was significantly increased at three days (2.2 ± 0.6 vs 1.2 ± 0.1 in controls, P < 0.01). There was also an early increase in platelets in glomeruli of diabetic animals, and platelet depletion significantly inhibited the early phase of proliferation. In addition to mesangial cell proliferation, a prominent glomerular macrophage infiltration began at day three and peaked at day 30 (3.94 ± 1.47 vs. 2.08 ± 1.13 in controls, P < 0.01). TGF-β mRNA increased at days 14 and 30. Insulin treatment prevented mesangial cell proliferation, actin expression, and macrophage infiltration, and normalized TGF-β expression at 14 and 30 days. These multiple cellular events preceded any detectable increases in glomerular gene expression or deposition of collagen I, IV or laminin.
Original language | English (US) |
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Pages (from-to) | 935-944 |
Number of pages | 10 |
Journal | Kidney international |
Volume | 47 |
Issue number | 3 |
DOIs | |
State | Published - Mar 1995 |
Funding
Financial support for the investigations of the authors provided from grants from the Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICIT) and from Asociación de Amigos del Riñón, Maracaibo, Venezuela, grant 3060 from CONACYT, Mexico and NIH grants DK-52121 and HL-68607.
ASJC Scopus subject areas
- Nephrology