Related Experiment Videos
Dynamics of connective matrix deposition in acute experimental E. coli pyelonephritis in rats
W L Santos1, Z A Andrade, H Rocha
1Gonçalo Moniz Research Center (FIOCRUZ), Salvador, Bahia, Brazil.
Abstract:
Adult male rats were subjected to pyelonephritis by direct kidney intramedullary injection of 0.1 ml saline suspension of 10(5) E. coli. Animals were killed at intervals of 4, 10, 15, 30 and 60 days. Half of each kidney and bladder were cultured in proper bacteriologic media to demonstrate the existence of infection. The other halves were submitted to light microscopy and ultrastructural studies. Immunofluorescence methods were used for the study of connective matrix components, at the initial stage of the inflammatory process (4, 10 and 15 days). Infection was documented by bacteriologic, gross and microscopic findings in all groups following inoculation, and it lasted up to two months. Following the acute inflammatory reaction, fibronectin and type III collagen were deposited in the interstitium of kidneys. Small amounts of type I collagen were found later. Type IV collagen appeared in small quantities, associated with collapse of structures containing basement membranes. Fibronectin became concentrated in re-activated foci. The subsequent scarring and associated focal renal atrophy depended upon the extension of the acute lesion.
Insights
This study details how Escherichia coli (E. coli) infection causes kidney damage in rats. It shows that inflammation leads to scarring and atrophy, impacting kidney structure and function.
Area of Science:
- Nephrology
- Pathology
- Microbiology
Background:
- Pyelonephritis, a kidney infection, can lead to significant renal damage.
- Understanding the early cellular and matrix changes is crucial for developing targeted therapies.
Purpose of the Study:
- To investigate the temporal changes in renal connective matrix components during experimental pyelonephritis.
- To correlate these matrix changes with the development of kidney scarring and atrophy.
Main Methods:
- Induction of pyelonephritis in adult male rats using Escherichia coli (E. coli).
- Bacteriological, histological, ultrastructural, and immunofluorescence analyses of kidney tissues at various time points (4-60 days).
Main Results:
- Persistent E. coli infection was confirmed for up to two months.
- Acute inflammation was followed by interstitial deposition of fibronectin and type III collagen.
- Later stages showed type I collagen, type IV collagen associated with basement membrane collapse, and fibronectin accumulation in reactive foci.
- Renal scarring and atrophy correlated with the extent of the initial acute lesion.
Conclusions:
- Experimental pyelonephritis induces significant alterations in renal connective matrix composition.
- These matrix changes, particularly fibronectin and collagen deposition, are key events in the pathogenesis of renal scarring and atrophy following infection.