急性腎不全ラットの近位尿細管におけるEPidermal growth factor局在の意義

抄録

Increasing evidence supports the hypothesis that epidermal growth factor (EGF) may have a role in the repair of tubular injury on acute renal failure (ARF). On the other hand, platelet-depletion reduces the renal damage in experimental ARF rats. We investigated the expression of EGF in the renal tissues of mercuric-choloride (HgCl₂, 2mg/kg)-induced ARF rats with (group-1) or without (group-2) platelet depletion for clarification of the role of EGF in the recovery of the renal tubules after ARF. Platelet-depletion was accomplished by the injection of anti-rat platelet serum (APS) 24 hours prior to the induction of ARF. The tubular necrosis and deterioration of renal function were significantly suppressed in group-1 compared with group-2 24 hours after HgCl₂ injection (S-Cr 0.60±0.17 mg/dl, Ccr0.58±0.11 ml/min in group-1 and 1.45±0.10 mg/dl, 0.20±0.02 ml/min in group-2, p<0.05) but were in the same range between both groups 12 hours after (S-Cr 0.75±0.03 mg/dl, Ccr 0.49±0.02 ml/min in group-1 and 0.60±0.05 mg/dl, 0.67±0.08 ml/min in group -2). By immunohistochemistry, EGF was localized in the ascending limbs of Henle and distal convoluted tubules in normal rats. However, in both ARF rats, EGF was stained on the proximal tubules, including the necrotic area as well as the ascending limbs of Henle and distal convoluted tubules, both 12 and 24 hours after ARF induction. Furthermore, in comparison with two ARF rat groups, the staining intensity of EGF was more prominent in group-1 than group-2 at both the 12- and 24-hour periods. These results indicate that EGF is a potent mediator in the repair of tubular injury on ARF.