Expression of growth factors after the release of ureteral obstruction in the rat kidney

Abstract

Background: Little is known about the mechanisms underlying recovery from hydronephrosis. Using a rat kidney model, we investigated the possible contribution of growth factors during regeneration after hydronephrosis.

Methods: After the unilateral ureteral obstruction for 7 days, the obstruction was released by ureterocystostomy. Epidermal growth factor (EGF), hepatocyte growth factor (HGF) and transforming growth factor-beta1 (TGF-beta1) were studied using immunohistochemistry and semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR).

Results: The immunoreaction of EGF in the medulla of both obstructed and contralateral kidneys increased after releasing the obstruction. The release of ureteral obstruction brought further increased immunoreaction of HGF to both the cortex and the medulla of the contralateral kidney. The immunoreaction of TGF-beta1 also increased in the interstitium especially around the blood vessels in the post-obstructed kidney. The expression of HGF and EGF mRNA in both kidneys and TGF-beta1 mRNA in the obstructed kidney were increased after releasing the obstruction.

Conclusions: These results suggest that various growth factors may be involved in the post-obstructive tubular recovery and interstitial damage in the rat kidney.