Increase production of fibronectin by glomerular cultures from rats with nephrotoxic nephritis. Macrophages induce fibronectin production in cultured mesangial cells.
BACKGROUND
The participation of monocytes-macrophages and their products in the pathogenesis of several types of glomerulonephritis has become increasingly evident. One of the most important aspects is the potential stimulation of monocyte-macrophages of the extracellular matrix. Therefore, production of fibronectin (FN) by glomeruli of rats with nephrotoxic nephritis was studied. In addition, the effect of macrophage-conditioned medium and interleukin-1 on FN production by cultured mesangial cell (MC) was tested.


METHODS
Nephrotoxic nephritis was induced in rats by injection of nephrotoxic serum and glomeruli obtained at different periods of time from nephritic and normal animals were cultured. FN in glomerular supernatants was determined by enzyme-linked immunosorbent assay and newly synthesized FN by incorporation of [35S]-methionine. Macrophage-conditioned medium was obtained from cultures of peritoneal resident macrophages and elicited macrophages by different stimuli. MC were cultured with or without macrophage supernatant or interleukin-1 and FN content from MC supernatants was determined by enzyme-linked immunosorbent assay.


RESULTS
These data show increase amounts of FN in nephritic cultures when compared with saline controls (time of nephritis; day 4: 3.9-, day 8: 4.35-, and day 18: 2.68-fold increase in FN) and experiments of newly synthesized FN by incorporation of [35S]-methionine had similar results. Macrophage-conditioned medium had FN stimulatory effect on cultured MC but interleukin-1 did not.


CONCLUSIONS
These data suggest: (a) that there is an increased newly synthesized FN production in glomeruli from rats with nephrotoxic nephritis, (b) that macrophage produce a FN-stimulatory factor(s) for MC, and (c) that this stimulatory factor probably is not interleukin-1.
Mosquera
J A
JA
Instituto de Investigaciones Clínicas, Universidad del Zulia, Maracaibo, Venezuela.
D000818:Animals; D005260:Female; D005353:Fibronectins / Q000096:biosynthesis*; D005455:Fluorescent Antibody Technique; D005920:Glomerular Mesangium / Q000378:metabolism* / Q000473:pathology; D007106:Immune Sera / Q000506:poisoning; D007375:Interleukin-1 / Q000494:pharmacology; D007668:Kidney / Q000187:drug effects; D007678:Kidney Glomerulus / Q000378:metabolism* / Q000473:pathology; D008264:Macrophages / Q000502:physiology*; D009393:Nephritis / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D011917:Rats, Inbred Lew; D011994:Recombinant Proteins
D005353:Fibronectins; D007106:Immune Sera; D007375:Interleukin-1; D011994:Recombinant Proteins