title: Phenotypic expression of collagen types in mesangial matrix of diabetic and nondiabetic rats.
abstract: This study was performed to evaluate the composition of the extracellular matrix of the mesangium in both diabetic and nondiabetic rats. Four groups of rats (n = 10 each) were studied. Nondiabetic rats were injected with saline (group 1) or insulin (3.5 U NPH daily) (group 2). Streptozocin-induced diabetic rats were similarly injected with saline (group 3) or insulin (group 4). Six weeks after initiation of study, glomerular diameter (micron) was increased in groups 2 (147 +/- 21), 3 (144 +/- 22), and 4 (150 +/- 7) compared with group 1 (104 +/- 12) (P less than .01). Glomerular hypertrophy was associated with an increase in the relative amount of mesangial matrix as determined by staining for fibronectin. By immunofluorescence microscopy (0-4+ scale), type I collagen antigen was not detected in the mesangium of any of the experimental groups. Staining for type V collagen and thrombospondin was similar between the experimental groups. Type III collagen antigen was not detected in the mesangium of control (group 1) or insulin-deficient diabetic rats (group 3); however, it was detected (2-3+) in the mesangium of both insulin-treated diabetic and nondiabetic rats (Mann-Whitney, P less than .01). Comparable intensity of staining (1+) for type IV collagen antigen was detected in the mesangium of animals from groups 1, 2, and 4; however, the staining intensity was markedly increased (3+) in insulin-deficient diabetic rats (group 3; Mann-Whitney, P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Medicine, Veterans Administration Medical Center, Seattle, WA 98108.
authors.forename: C K
authors.initials: CK
authors.lastname: Abrass
authors.forename: C V
authors.initials: CV
authors.lastname: Peterson
authors.forename: G J
authors.initials: GJ
authors.lastname: Raugi
mesh_terms: D000818:Animals; D003094:Collagen / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D003928:Diabetic Nephropathies / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D005920:Glomerular Mesangium / Q000378:metabolism*; D006801:Humans; D008297:Male; D008856:Microscopy, Fluorescence; D010641:Phenotype; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D005353:Fibronectins; D003094:Collagen