Abstract: AIM: To evaluate effect of active immunization with peptide ATR12181 from the extracellular parts of AT1 receptor on reducing microalbuminuria of SHRs. METHODS: SHRs and Wistar rats were immunized actively by ATR12181, the synthesized peptide from the extracellar part of AT1 receptor. Another SHR group was given Losartan (10 mg·kg^-1·d^-1) orally by gastric gavage once a day in morning. The specific serum antibody titer and 24h urinary albumin excretion were detected by ELISA, the Systolic Blood Pressure(SBP) of SHR was measured consecutively, and the mRNA of AT1R, cfos, c-jun in kidney were measured by RT-PCR. RESULTS: The antibodies to ATR12181 were detected both in immulized SHRs (SHR-I) and WISTAR rats (WISTAR-I). At 20 weekends, SHR-I group got a lower SBP (145 mm Hg±8 mm Hg) than SHR-C group (197 mm Hg±8 mm Hg),but no significant difference compared with the SHR-L group (139 mm Hg±17 mm Hg, P>0.05). The SBP of WISTAR-I group was normal (116 mm Hg±6 mm Hg). 24 h urinary albumin excretion both in SHR-I group and SHR-L group were significantly lower than that of SHR-C group (P< 0.05); The mRNA of the AT1R, c-fos, c-jun were significantly lower in SHR-I group and SHR-L group. CONCLUSION: ATR12181 vaccine may produce high titer antibody, that reduce the blood pressure, and decrease urinary protein excretion in SHR.

Key words: spontaneously hypertensive rats, ATR12181 vaccine, kidney, microalbuminuria