The Effects of High‐Sodium Intake on Systemic Blood Pressure and Vascular Responses in Spontaneously Diabetic WBN/Kob‐Leprfa/fa Rats

Summary The prevalence of type 2 diabetes mellitus (T2DM) and hypertension has markedly increased worldwide. The purpose of the present study was to examine the effects of a high-salt intake on the systolic blood pressure (SBP) and vascular responses in WBN/Kob-Leprfa/fa (WBKDF) rats, a new spontaneous animal model of T2DM. Male WBKDF rats and age-matched Wistar rats at 6 weeks of age were each divided into two groups and fed either a normal-sodium (0.26%, NS) diet or high-sodium (8%, HS) diet for 14 weeks: 1) Wistar rats on NS diet (Wistar-NS); 2) Wistar rats on HS diet (Wistar-HS); 3) WBKDF rats on NS diet (WBKDF-NS); 4) WBKDF rats on HS diets (WBKDF-HS). Neither WBKDF-NS nor Wistar-NS rats showed significant changes in SBP throughout the experiment, but both WBKDF-HS and Wistar-HS exhibited significant elevation of SBP, which was more prominent (P<0.01) in WBKDF-HS than in Wistar-HS. Phenylephrine-induced contractions of isolated thoracic aortic rings were significantly (P<0.01) enhanced in WBKDF-HS and Wistar-HS compared with the respective strain of rats on the NS diet. In contrast, acetylcholine- and nitroprusside-induced relaxation were significantly (P<0.01) diminished in both WBKDF-HS and Wistar-HS, and these HS diet-induced changes were more profound (P<0.01) in WBKDF rats than in Wistar rats. Significantly (P<0.05) higher plasma concentrations of 8-iso-prostaglandin F2α and sodium ions were observed in WBKDF-HS than in Wistar-HS. The current study demonstrated that WBKDF-HS rats developed salt-sensitive hypertension associated with vascular dysfunction. The WBKDF rat may be a useful model for investigating the etiology of hypertension with T2DM. This article is protected by copyright. All rights reserved.