Phenotypic changes and cell cycle activation in early tubulointerstitial injury of rat adriamycin nephrosis

• Published in: Pathology international Vol. 52; no. 3; pp. 214 - 223
• Main Authors: Shu, Yujing, Hoshi, Sachi, Tomari, Shinsuke, Watanabe, Teruo, Nagata, Michio
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Pty 01.03.2002
• Subjects: Actins - metabolism; adriamycin; Animals; Antibiotics, Antineoplastic - toxicity; cell cycle; Cell Cycle - drug effects; Disease Models, Animal; DNA Fragmentation - drug effects; Doxorubicin - toxicity; Glomerulosclerosis, Focal Segmental - chemically induced; Glomerulosclerosis, Focal Segmental - metabolism; Glomerulosclerosis, Focal Segmental - pathology; Immunohistochemistry; In Situ Nick-End Labeling; kidney; Kidney Tubular Necrosis, Acute - chemically induced; Kidney Tubular Necrosis, Acute - metabolism; Kidney Tubular Necrosis, Acute - pathology; Kidney Tubules - drug effects; Kidney Tubules - pathology; Male; Nephritis, Interstitial - chemically induced; Nephritis, Interstitial - metabolism; Nephritis, Interstitial - pathology; Osteopontin; Phenotype; phenotypic change; proliferating cell nuclear antigen; Proliferating Cell Nuclear Antigen - metabolism; Proteinuria; rat; Rats; Rats, Sprague-Dawley; Sialoglycoproteins - metabolism; Time Factors; tubulointerstitial injury; Vimentin - metabolism; α-smooth muscle actin
• ISSN: 1320-5463; 1440-1827
• DOI: 10.1046/j.1440-1827.2002.01339.x

Tubular response, including phenotypic changes against a variety of injuries, is an initial event that promotes tubulointerstitial injuries. Using the progressive kidney disease model of rat adriamycin (ADR) nephrosis, the present study focused on the cell cycle activation and phenotypic changes that occur in the tubuli in early tubulointerstitial injury in ADR nephrosis. At 12 weeks, experimental animals developed overt nephrosis with tubulointerstitial injury, which correlated well with the degree of proteinuria and incidence of glomerulosclerosis. Initial pathology of the tubuli showed a slight dilatation of tubuli, which tended to occur in individual nephrons. Immunohistochemistry demonstrated that vimentin‐positive tubuli and osteopontin (OPN)‐positive tubuli were associated mostly with proliferating cell nuclear antigen expression. Protein levels of OPN in the renal cortex were correlated with the level of proteinuria by western blotting. Vimentin‐ and OPN‐expressing tubuli were tightly associated with a peritubular influx of α‐smooth muscle actin (SMA)‐positive cells or ED‐1‐positive cells. In addition, we found thrombomodulin+/ TUNEL+ (dUTP‐biotin nick‐end labeling) peritubular endothelial cells and ED‐1+/α‐SMA+ cells at an early stage among interstitial inflammatory cells. These results suggest that cell cycle activation in tubular cells forms the background for the phenotypic tubular changes that are involved in chronic tubulointerstitial injury in ADR nephrosis.