EXPRESSION AND DISTRIBUTION OF EPIDERMAL GROWTH-FACTOR IN ACUTE AND CHRONIC RENAL-ALLOGRAFT REJECTION

Expression and distribution of epidermal growth factor in acute and ch ronic renal allograft rejection. Epidermal growth factor (EGF) is a fi brogenic cytokine with a possible role in chronic damage. EGF is also involved in tubular regenerative response to injury. This study invest igates the expression and distribution of EGF in a rat model of renal allograft rejection. EGF was localised in control kidneys to distal co nvoluted tubules (DCT) and thick ascending loop of Henle (TAL). Five d ays post-transplantation EGF was diffusely distributed. In chronic rej ection at one, three and six months, damaged areas of allografts demon strated faint diffuse EGF staining, while well-preserved areas exhibit ed the normal distribution pattern. PreproEGF mRNA was significantly r educed (P < 0.01) in acute rejection and in chronic rejection at three months to 28% and 51% of normal, respectively. At six months values r anged from 16% to 166% of normal kidneys, and were inversely correlate d with tubular damage (P < 0.01). PreproEGF mRNA was localized to DCT and TAL in controls and in well preserved areas of the tissue in chron ic rejection. Thus, EGF would not appear to contribute to the developm ent of injury in chronic renal rejection. It may instead exert a prote ctive effect on tubular structures.