Increases in blood pressure occur prior to significant elevations in weight in a diet‐induced life‐long obesity rat model

Abstract

Obesity is at epidemic proportions, impacting both adults and children resulting in various health complications, including hypertension. We hypothesized that juvenile rats fed a high fat diet (HF) from weaning would have elevated blood pressure. Male Sprague Dawley rats were fed either HF or normal chow (NC) diets from 3 weeks of age. At four weeks animals had femoral arterial radiotelemetry transmitters implanted for mean arterial pressure (MAP) and heart rate (HR) measurements for 17 weeks. [DA1]After 2 weeks on the HF diet there was a significant increase in MAP compared to NC rats (95 + 1 vs. 92 + 1 mm Hg; p<0.05); the difference in blood pressure between the HF and NC rats increased throughout the study. Interestingly, it wasn't until 10 weeks of HF and NC diet that the body weight significantly differed (370 + 6 vs. 343 + 6 grams; p<0.05). At the conclusion of the study HF rats had significantly greater MAP (127 + 2 mm Hg) and body weight (471 + 5 g) compared to NC rats (113 + 3 mm Hg) (416 + 10g). MAP fall in response to ganglionic blockade was also slightly lower in HF compared to NC rats (p=0.07). In conclusion, elevations in MAP in response to a HF diet precede significant increases in body weight. Further studies will clarify the mechanism by which the increase in MAP prior to the weight gain occurs.