Increased TGF-α and EGF Receptor mRNA Expression in Response to Neonatal Unilateral Partial Ureter Obstruction in Rats

Abstract

Aim: To evaluate the potential role of members of the epidermal growth factor (EGF) family in altered renal growth caused by partial ureteral obstruction in the developing obstructed and non-obstructed kidneys. Methods: During anesthesia either the upper fourth (n = 6–7) or the upper two-thirds of the left ureter (n = 6–7) were embedded into the psoas muscle in newborn rats resulting in mild or severe partial unilateral obstruction, respectively, which was maintained during the following 24 weeks. Sham-operated control rats were prepared in parallel (n = 6–7). Real time PCR assays were used to quantify mRNA encoding EGF, TGF-α, HB-EGF and EGF receptor. The expression of ribosomal RNA was determined to relate the specific mRNA expression of members of the EGF system. Results: Relative expression of TGF-α and EGF receptor mRNA levels were elevated significantly both in the severe and mild obstructed kidney compared with the contralateral or sham-operated kidneys after 24 weeks of obstruction. However, the expression of neither EGF nor HB-EGF was changed after obstruction. Conclusion: The increased expression of TGF-α and its receptor in the obstructed kidney might be related to a cell-survival function in the affected cells possibly by protecting them from entering apoptosis.