Abstract
Background: Major health issues stem from obesity, which has spurred the biological research t1cld to find solutions to these life-threatening diseases as diet-induced type II diabetes and hypertension. In order to understand health related issues, research models must be well understood. The Nile rat is a novel model for type 2 diet induced diabetes and the metabolic syndrome. One major aspect of metabolic syndrome is hypertension; therefore, to develop a more complete understanding of this new rat model and eventually the disease, blood pressure must be evaluated and categorized to determine a possible similarity to human pathophysiology. Purpose: The purpose is to develop the blood pressure perspective in the Nile rat model by evaluating the relationship between blood pressure and factors that evolve in the development of the metabolic syndrome. Methods: Three studies were conducted. In the first study, 23 wk old male Nile rats fed a high. carbohydrate diet were followed for 20 wks to determine blood pressure trends in the development of the metabolic syndrome in the male model. In the second sn1dy, young female Nile rats, fed the same high-carbohydrate diet, were followed to determine the pattern of blood pressure with the development of the metabolic syndrome in the female model. Tn the third study, female Nile rats fed a high fat diet were followed for 6 wks to determine dietary influences on blood pressure. Results: In all three studies the animals separated into early and late-onset diabetic groups based on when their fasting blood glucose surpassed 110 mg/dL. In male rats fed a high-carbohydrate diet a significant separation in blood pressure was observed between the early-onset and late onset rats, whereas female blood pressures did not differ in early-onset and late-onset groups, but female rats had u lower blood pressure and fasting blood glucose on average than the male rats. In both genders, blood pressure positively correlated with age and in the females the blood pressure in early-onset animals positively correlated with kidney function (BUN). High-carbohydrate and high-fat diets fed to the females affected blood pressure equally. Conclusion: The hypothesis that blood pressure in male and female Nile rats correlate with the progression of the diabetes (metabolic syndrome) in the Nile rat was confirmed. In the female model, where more parameters were measured, blood pressure correlated best with renal failure, also a common aspect of type 2 diabetes in humans. The female Nile rats were somehow protected from the same hypertension that occurred in the male rats.