The development of glomerular
sclerosis in benign
nephrosclerosis (
BNS) was studied. We investigated the intraglomerular expression of type III and IV
collagens and their mRNAs by immunohistochemistry and by the in situ hybridization method.
Formalin-fixed
paraffin sections from 28 patients with
BNS and 10 control cases were stained by the
avidin-
biotin complex (ABC) method using
monoclonal antibodies for human type III and IV
collagens. In the course of the sclerotic process of the glomerulus in
BNS, the glomerular staining intensity of
type IV collagen increased. The strongest staining was observed in the glomerulus at the early sclerotic stage, and intensity decreased slightly at the later stages. Although
type III collagen was absent in normal and nonsclerotic glomeruli, peripheral regions of the sclerotic glomeruli were positive at the early sclerotic stage. Later,
type III collagen was diffusely observed in the completely hyalinized glomeruli. The expression of type III and
type IV collagen mRNAs was detected in the glomeruli of
BNS by the non-radioactive in situ hybridization method using
thymine-
thymine (T-T) dimerized synthetic
oligonucleotides. The number of
mRNA positive cells for type III and type IV
collagens increased at the presclerotic and early sclerotic stages. But these cells gradually decreased in number as glomerular
sclerosis developed. We concluded that
type III collagen was presumably synthesized by the intraglomerular cells and may contribute to the development of glomerular
sclerosis in
BNS along with
type IV collagen.