Effect of Unilateral Ureteral Obstruction(UUO) on the Expression of Platelet-Derived Growth Factor(PDGF) in the Sprague-Dawley Rat

Park, Young Kwan; Kim, Mi Kyung; Choi, Jeong Hoon; Yoo, Kee Hwan; Hong, Young Sook; Lee, Joo Won; Kim, Soon Kyum

Abstract

Unilateral ureteral obstruction(UUO) results in severe renal vascular constriction through the activation of renin-angiotensin system, which causes progressive tubulointerstitial fibrosis. Platelet-derived growth factor(PDGF) plays an important role in stimulating myofibroblasts and regulating synthesis of extracellular matrix in renal interstitial proliferation and fibrosis. This study was designed to investigate the relationship between unilateral ureteral obstruction and PDGF expression in tubulointerstitial fibrosis of the kidney. Eleven adult male Spraugue-Dawley rats were carried out unilateral ureteral ligation and sham operation. After 14 days, control kidney, UUO kidney and intact opposite(IO) kidney were harvested. Tissue fibrosis was quantified morphologically using the point detection method after Masson-Trichrome stain. Expression of PDGF-A and B was determined by immunohistochemical staining, RT-PCR and Western blot assay.
Results
were as follows: 1) UUO and IO group resulted in reduced kidney weight compared with control group(p<0.05). 2) Collagen deposition was increased in the renal cortex of UUO group(p<0.05). 3) PDGF-A and B mRNA expression was increased significantly compared with control and IO group(p< 0.05). 4) PDGF-A and B protein expression were increased in UUO and IO group(p<0.05). 5) On the immunohistochemical staining for PDGF- A and B, staining intensity was increased significantly at the renal cortex, interstitium and tubular epithelial cells in the UUO group. This results indicated that PDGF-A and B plays important role in tubulointerstitial fibrosis developed after unilateral ureteral obstruction and compensatory fibroproliferative growth in contralateral kidney.