The Effects of High Dietary Lard on Hypertension Development in Spontaneously Hypertensive Rats

Blueberry intervention improves vascular reactivity and lowers blood pressure in high-fat-, high-cholesterol-fed rats

Growing evidence suggests that intake of flavonoid-containing foods may exert cardiovascular benefits in human subjects. We have investigated the effects of a 10-week blueberry (BB) supplementation on blood pressure (BP) and vascular reactivity in rats fed a high-fat/high-cholesterol diet, known to induce endothelial dysfunction. Rats were randomly assigned to follow a control chow diet, a chow diet supplemented with 2 % (w/w) BB, a high-fat diet (10 % lard; 0·5 % cholesterol) or the high fat plus BB for 10 weeks. Rats supplemented with BB showed significant reductions in systolic BP (SBP) of 11 and 14 %, at weeks 8 and 10, respectively, relative to rats fed the control chow diet (week 8 SBP: 107·5 (SEM 4·7) v. 122·2 (SEM 2·1) mmHg, P= 0·018; week 10 SBP: 115·0 (SEM 3·1) v. 132·7 (SEM 1·5) mmHg, P< 0·0001). Furthermore, SBP was reduced by 14 % in rats fed with the high fat plus 2 % BB diet at week 10, compared to those on the high-fat diet only (SBP: 118·2 (SEM 3·6) v. 139·5 (SEM 4·5) mmHg, P< 0·0001). Aortas harvested from BB-fed animals exhibited significantly reduced contractile responses (to L-phenylephrine) compared to those fed the control chow or high-fat diets. Furthermore, in rats fed with high fat supplemented with BB, aorta relaxation was significantly greater in response to acetylcholine compared to animals fed with the fat diet. These data suggest that BB consumption can lower BP and improve endothelial dysfunction induced by a high fat, high cholesterol containing diet.

Rat chromosome 8 confers protection against dyslipidemia caused by a high-fat/low-carbohydrate diet

BACKGROUND/AIMS

Recent studies have highlighted the importance of gene by diet interactions in contributing to risk factors of metabolic syndrome. We used a consomic rat panel, in which a chromosome of the Brown Norway (BN) strain is introgressed onto the background of the Dahl salt-sentitive (SS) strain, to test the hypothesis that these animals will be useful for dissecting gene by diet interactions involved in metabolic syndrome.

METHODS

We placed the parental SS and BN strains on a low-fat/high-carbohydrate (LF) or high-fat/low-carbohydrate (HF) diet for 22 weeks and measured several indices of metabolic syndrome. We then investigated the effect of diet in eight consomic rat strains.

RESULTS

We show that the HF diet resulted in significantly increased levels of fasting plasma cholesterol and triglycerides in the SS strain, with no effect in the BN. Both strains responded to the HF diet with slight increases in body weight. SSBN8 was the only consomic strain that resembled that of the BN, with low levels of fasting cholesterol and triglycerides even on the HF diet.

CONCLUSIONS

These results indicate that BN chromosome 8 harbors a gene or genes that confer protection against dyslipidemia caused by the HF diet.