Expression of tenascin in mesangial injury in experimental glomerulonephritis.
The distribution of tenascin (TN) in the kidneys in relation to embryogenesis, the normal glomerulus and various glomerular diseases has been studied immunohistochemically. However, the existence of TN protein and mRNA simultaneously has never been reported in reversible mesangial proliferative glomerulonephritis (MPGN). In this study, by immunohistochemical methods and in situ hybridization, we investigated the expression of TN in injury to glomerular mesangial cells. Anti-Thy 1.1 mesangial proliferative glomerulonephritis was induced in Wistar rats by injection of antirat thymocyte plasma. After injection, the rats were sacrificed on days 4, 7, 10 and 14. Immunohistochemically, slight staining of TN was detected in normal glomeruli. An increase in staining was observed in the mesangial areas during the mesangial proliferative phase (days 4, 7 and 10). It decreased on day 14. Focal staining of TN in Bowman's capsule and the periglomerular region was also noted during the mesangial proliferative phase. TN mRNA could not be detected in normal glomeruli by in situ hybridization, but it was observed in the mesangial areas during the mesangial proliferative phase. Focal expression of TN mRNA was noted in Bowman's capsular epithelial cells and periglomerular cells after injection. TN mRNA-positive cells were localized to mesangial, Bowman's capsular and periglomerular areas of hypercellularity and were significantly associated with an increase in TN staining areas. In conclusion, the results of this study prove that TN is a component of the normal mesangial matrix, and that it is induced by mesangial, Bowman's capsular and periglomerular cells after mesangial injury. We could not determine the role of TN in Bowman's capsular and periglomerular areas, but a reversible MPGN model has been reported to show an irreversible progressive course in TN knockout mice. In reversible MPGN it is considered that the role of TN in the mesangial areas may be related to the process of mesangial repair.
Jyo
Y
Y
Department of Medicine, Kawasaki Medical School, Okayama, Japan.
Sasaki
T
T
Nomura
S
S
Tamai
H
H
Kawai
S
S
Osawa
G
G
Nakao
N
N
Kusakabe
M
M
D000818:Animals; D002455:Cell Division; D004848:Epithelium / Q000473:pathology; D005920:Glomerular Mesangium / Q000737:chemistry* / Q000473:pathology*; D005921:Glomerulonephritis / Q000378:metabolism / Q000473:pathology*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D019063:Tenascin / Q000032:analysis* / Q000235:genetics
D012333:RNA, Messenger; D019063:Tenascin