FEMALE MICE ARE NOT PROTECTED FROM ELEVATED BLOOD PRESSURE INDUCED BY CONSUMING A DIET HIGH IN SALT AND FRUCTOSE: High Salt + High Fructose Diet and Blood Pressure in Mice

Background: Research demonstrates that important sex differences exist in dietary-induced increase in blood pressure. The objective of this study was to investigate sex differences in blood pressure and renal handling of sodium in mice consuming a high-salt and high-fructose (HSHF) diet.

Methods: Healthy 4-week-old male and female mice (n=6/group) were placed in metabolic cages for six weeks. After the baseline week all mice consumed the HSHF diet consisting of 4% salt chow with a drinking solution of 20% fructose and 1% NaCl for 4 weeks. This was followed by a recovery week with mice on the normal diet with water. Blood pressure was measured daily via the tail cuff technique. Daily measurements of sodium intake and output were measured. Real-time PCR was conducted to measure relative expression of key renal sodium transporters.

Results: Systolic blood pressure (SBP) significantly increased in male and female mice during the HSHF period. SBP decreased in male mice in the recovery week but remained elevated in female mice. Female mice showed higher sodium retention during the HSHF period via the Nae/Nai ratio (62±5% vs 75±5%, p<0.01). Molecular expression of renal sodium transporters was significantly higher in the female mice.

Conclusion: We conclude that female mice are not protected from the HSHF dietary-induced increase in blood pressure. Higher sodium retention might explain the lack of protection in female mice. This study challenges the current position that females possess protective mechanisms against dietary induced increase in blood pressure, at least with high fructose.