Figure 7. Blood pressure, renal outer-medullary oxidative stress and tubulointerstitial injury in wild-type and HV1 mutant Dahl salt-sensitive rats.

a) average 24 hour mean arterial pressure as measured by radio-telemetry over the final 3 days of high (8%) NaCl feeding for two weeks in wild-type (WT; open columns) and HV1^−/− mutant (M; closed columns) maintained on either vehicle (right) or given the NHE-1 inhibitor KR32568 (2mg/kg/day) from day 4 of high salt feeding (left). b) 24 hour daily mean arterial blood pressures (mmHg) as measured by radio-telemetry during 0.4% NaCl control (C) and 8% high salt (HS) feeding for 14 days (D). Open circles, wild type (n=12); closed circles, HV1^−/− mutant (n=12). All animals received only vehicle infusions until day 3 of high salt feeding (D3-HS). Drug or vehicle infusions were maintained until day 14 of high salt feeding (D14-HS). c) outer-medullary oxidative stress as determined by anti-4-HNE staining of the outer-medullary region. Shown are representative images of anti-4HNE staining in the outer-medulla and papilla of vehicle treated wild-type (left) and HV1^−/− mutant rats (right) demonstrating more intense membrane staining of mTAL in wild-type animals. d) outer-medullary protein casts (% outer-medullary area). Shown are representative trichrome stained images of the outer-medulla vehicle treated wild-type (left) and HV1^−/− mutant rats (right) demonstrating greater % area containing of brightly colored protein casts in wild-type animals. All histological measurements were assessed at the end of the study after 14 days of high salt feeding. Data are mean±SE. All data were compared with 2-way ANOVA.