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The effect of defibrination on macrophage participation in rabbit nephrotoxic nephritis: studies using glomerular
Abstract:
Recent studies in experimental crescentic glomerulonephritis, using the technique of glomerular culture, have shown that the macrophage is a major cell type present within the glomeruli and developing crescents. It has been suggested that their accumulation is a consequence of glomerular fibrin deposition. The effect of defibrination with ancrod on the cellular events occurring in experimental crescentic glomerulonephritis in the rabbit was therefore assessed in this disease using the techniques of culture of isolated glomeruli, electronmicroscopy or renal tissue, and light microscopy. Defibrinated animals developed only minimal renal impairment, virtually no fibrin deposition in Bowman's Space and only a mild degree of crescent formation, in contrast to the severe renal failure, fibrin deposition and crescent formation that occurred in the untreated animals. The culture of isolated glomeruli and electronmicroscopy of intact renal tissue demonstrated large numbers of macrophages within and emerging from glomeruli of both defibrinated and untreated animals. However, only in untreated animals were macrophages seen to migrate into Bowman's Space, phagocytose fibrin, transform into epithelioid cells and accumulate to form crescents. These studies suggest that fibrin deposition in Bowman's Space is the major stimulus to the macrophage migration from capillary loops and accumulation in Bowman's Space. However, fibrin deposition does not appear to be the stimulus to macrophage accumulation within capillary loops as this event was not affected by defibrination.
Insights
Fibrin deposition in Bowman's space, not within glomeruli, drives macrophage accumulation and crescent formation in experimental glomerulonephritis. Defibrination significantly reduced kidney damage by preventing this crucial fibrin deposition.
Area of Science:
- Nephrology
- Immunology
- Pathology
Background:
- Macrophages are key cells in experimental crescentic glomerulonephritis.
- Macrophage accumulation is hypothesized to result from glomerular fibrin deposition.
Purpose of the Study:
- To investigate the role of fibrin deposition in macrophage accumulation and crescent formation in experimental crescentic glomerulonephritis.
- To assess the impact of defibrination on the cellular events of this kidney disease.
Main Methods:
- Experimental crescentic glomerulonephritis induced in rabbits.
- Defibrination using ancrod.
- Glomerular culture, light microscopy, and electron microscopy of renal tissue.
Main Results:
- Defibrinated rabbits showed minimal renal impairment, reduced fibrin in Bowman's space, and mild crescent formation compared to untreated animals.
- Macrophages were abundant in glomeruli of both groups, but only in untreated animals did they migrate to Bowman's space, phagocytose fibrin, and form crescents.
- Defibrination did not affect macrophage accumulation within glomerular capillary loops.
Conclusions:
- Fibrin deposition specifically in Bowman's space is the primary stimulus for macrophage migration and crescent formation.
- Fibrin deposition within capillary loops does not appear to drive macrophage accumulation in this model.
- Targeting fibrin in Bowman's space may be a therapeutic strategy for crescentic glomerulonephritis.