Renal protective effects of blocking the intrarenal renin-angiotensin system: Angiotensin II type I receptor antagonist compared with angiotensin-converting enzyme inhibitor

The present study compared renoprotective effects of angiotensin II type I receptor antagonist (AT(1)RA) with angiotensin converting enzyme inhibitor (ACEI), and their influence on the renin-angiotensin-system (RAS). Experime ntal nephrotic syndrome was induced in SD rats by repeated peritoneal injec tions of puromycin. Twenty-eight rats were randomly divided into four group s: normal control, nephrotic control, ACEI-treated, and AT(1)RA-treated gro ups. Serum, urine, and renal tissue were collected for study at the end of 12 weeks. Compared with those of the nephrotic control group, urinary prote in was less and renal function was better in both treated groups. The glome rular and interstitial damage indexes of both ACEI- and AT1RA-treated rats were lower than those of nephrotic control rats, with no significant differ ence observed between the two treated groups. Local renal ACE activity and angiotensin II concentration were elevated in nephrotic rats (p < 0.01). Ho wever, there is no significant difference in circulating RAS, renal tissue renin, and aldosterone between the normal control and nephrotic control rat s. As expected, enalapril inhibited the local renal ACE activity and signif icantly decreased angiotensin II (p < 0.01). Intrarenal ACE activity and an giotensin concentration returned to normal levels after treatment with irbe sartan (p < 0.01). In conclusion, AT1RA and ACEI have comparable renal prot ective effects, and these protective effects were associated with the inhib ition of intrarenal ANG II.