Date of Award

8-2008

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Food Science and Human Nutrition

Advisor

Dorothy J. Klimis-Zacas

Second Committee Member

Anastasia Z. Kalea

Third Committee Member

Dale A. Schuschke

Abstract

The effect of wild blueberries on major endothelium-dependent vasodilation pathways and arterial blood pressure (BP) was examined in the young adult Spontaneously Hypertensive rat (SHR), used as a model of endothelial dysfunction, and the Wistar Kyoto (WK) rat, with functional endothelium, used as the control. Male SHR and WK rats were fed a control (SHR-C and WK-C), or a wild blueberry-enriched (SHR-B and WK-B) diet for nine weeks. By the age of 21 weeks, thoracic aortae were excised and 3mm arterial rings were prepared and immersed in Radnoti tissue baths. Rings were precontractred with phenylephrine (Phe) (10"6M), followed by cumulative acetylcholine (Ach) doses (10"9M to 3x10" 6M) to generate dose-response curves in the absence or in the presence of either a nitric oxide synthase (NOS) inhibitor (L-NMMA at 10"4M), a cyclooxygenase (COX) inhibitor (MFA at 10"5M) or both inhibitors added simultaneously. The maximum Ach-induced vasodilation force (Fmax) and vessel sensitivity (pD2) were determined for each treatment group. A two-way analysis of variance (ANOVA) demonstrated no significant difference in the Fmax between the WK-B and WK-C groups. However, wild blueberries were found to reduce the pD2 in response to Ach in the young adult WK rat (WKB: 7.41 ± 0.02 vs. WK-C 7.49 ± 0.02, p<0.05, n=9). In the young adult SHR, wild blueberries were shown to reduce Fmax in response to Ach (SHR-B: 92.13 ± 0.56 vs. SHR-C: 94.63 ± 0.56, p<0.05, n=10). This effect is mediated by the COX pathway, as shown by the increased Fmax in response to Ach with the COXpathway inhibition (SHR-B: 102.17 ± 0.57 vs. SHR-C: 97.76 ± 0.57, p<0.05, n=10). Furthermore, wild blueberries were shown to increase the pD2 of the young adult SHR aorta, when COX and NO pathways were inhibited separately, SHR-B: 7.72 ± 0.02 vs. SHR-C: 7.63 ± 0.02, p<0.05, n=10, and SHR-B: 7.17 ± 0.02 vs. SHR-C: 7.04 ± 0.02, p

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