LONG-TERM EFFECTS OF ENALAPRIL IN RAT WITH EXPERIMENTAL CHRONIC TUBULOINTERSTITIAL NEPHROPATHY

The aim of this study was to determine whether or not angiotensin-conv erting enzyme inhibitor, enalapril, could ameliorate the chronic tubul o-interstitial nephropathy (TIN) in uninephrectomized (UNx) rats. Chro nic TIN(M) was induced by 2-bromoethylamine hydrobromide. Rats were as signed to five groups; control, UNx-control (UNxC), UNx treated with e nalapril (UNxE), UNxMC and UNxME. Enalapril was given for 12 months as drinking water (50 mg/1). At 6 months, albuminuria in UNxE decreased significantly compared with UNxC, but without change in UNxM rats. By 12 months, although all rats in control, UNxC and UNxE remained alive, 1 and 4 rats died in UNxME and UNxMC, respectively. Albuminuria in UN xC was reduced significantly by enalapril but not in UNxM rats. Both u rine volume and urine osmolality became equal to control by enalapril in UNx rats, but not in UNxM rats. Serum cholesterol levels were norma lized by enalapril in UNx rats, but not in UNxM rats. Levels of serum creatinine and blood urea nitrogen were invariably higher in UNxM than in UNx rats, irrespective of enalapril. Glomerular sclerosis was stat istically decreased by enalapril in both UNx and UNxM rats. Enalapril reduced the overall tubulo-interstitial lesions in UNx rats, but not i n UNxM group. However, in UNxM rats tubular changes in medullary porti on were significantly ameliorated by enalapril. These data suggest tha t enalapril has a beneficial effect on chronic TIN in this model.