HIGH-SALT DIET CAUSES DROP IN BLOOD PRESSURE DURING DEVELOPMENT OF ONE-KIDNEY ONE-CLIP RENOVASCULAR HYPERTENSION IN FEMALE RATS

Abstract

Objective: The aim of this research was to study high-salt diet (HSD) impact on development of renovascular hypertension (RH) in male and female Wistar rats. Design and method: Male and female Wistar rats were divided into three groups. The RH/CTRL group had a standard diet (0.25% NaCl). The RH/HSD group gets HSD (4% of NaCl). The RH/DC group had HSD during the first 4 weeks of experiment only. After two-week diet adaptation period Goldblatt's one-kidney one-clip surgery was conducted for all groups of the animals. The RH dynamics was monitored for the next 5 weeks. Blood and urine samples were taken on the 1st, 4th and 7th weeks. Results: There was no diet impact on systolic blood pressure (SBP) before the surgery. In male rats after the surgery an accelerated blood pressure elevation in RH/HSD and RH/DC groups was observed on the 3rd week (mean ± SEM: RH/CTRL 151 ± 4 mm Hg; RH/DC 169 ± 10, p = 0.08; RH/HSD 176 ± 8, p < 0.05). Diet change in RH/DC group resulted in prevention of further elevation of SBP. The SBP in RH/DC group was lower than in RH/HSD group by the 7th week of the experiment (RH/HSD 188 ± 9 mm Hg; RH/CTRL 179 ± 6, p = 0.50; RH/DC 167 ± 5, p < 0.05). In female rats an acceleration of SBP elevation in RH/HSD and RH/DC groups was lower than that in male groups (RH/CTRL 159 ± 7 mm Hg; RH/DC 173 ± 7; RH/HSD 174 ± 6). The significant decrease of SBP was in RH/HSD and RH/DC groups on the 5th week (RH/HSD -29 ± 3; RH/DC -29 ± 10 mm Hg, p < 0.05). It was followed by the further elevation of blood pressure in RH/HSD group, but not in RH/DC group. SBP was lower in RH/DC group than in RH/HSD and RH/CTRL groups on the 7th week of the experiment (RH/HSD 175 ± 7 mm Hg; RH/CTRL 170 ± 9; RH/DC 141 ± 4). Creatinine clearance in male rats rises on the 4th week and decreases on the 7th week. In female there was a contrary dynamics. Conclusions: The influence of HSD on development of RH differs between male and female rats. In female rats HSD leads to a significant decrease of blood pressure during the third week of RH development.