Abstract 13462: Assessment of the Physiological and Pathological Structural Differences Along the Aorta in a Rat Model of Metabolic Syndrome

Abstract

Introduction: Vascular geometry may vary along the aortic length in normal and chronic disease conditions such as metabolic syndrome. Aim: This study investigated regional structural changes in the aorta in a rodent model of metabolic syndrome, the high-fat diet streptozotocin-induced diabetes mellitus (HFD-D). Methods: Four-week-old male Wistar albino rats received a control diet (CD) or high fat diet (HFD) for 10 weeks. On week 6, 40 mg/kg streptozotocin and its buffer were injected intraperitoneally into the HFD and CD groups, respectively. Glucose and insulin tolerance tests (GTT and ITT) and tail-cuff systolic blood pressure (SBP) were measured. At the end of the study, rats were euthanized, and the thoracic and abdominal aortic segments collected for histomorphometric analysis of aortic media thickness, medial cross-sectional area (CSA), elastic lamellae number, interlamellar spacing, collagen density and lipid deposit density. Results: HFD-D rats showed elevated GTT, ITT and SBP. Abdominal aortic segments of both CD and HFD-D rats showed smaller media thickness and CSA, lower elastin lamellae number and higher collagen density compared with the thoracic segments, suggestive of physiological rather than pathological structural differences in both groups. Elastin interlamellar spacing and lipid plaque deposits were higher in the abdominal aorta of the HFD-D relative to controls, indicating that early vascular pathological changes favor the abdominal aorta in HFD-D rats. Conclusions: In this disease model of metabolic syndrome, vascular structural changes are differentially expressed along the aorta, with pathological features limited to the abdominal rather than the thoracic aorta. These structural abnormalities may underlie the elevated blood pressure seen in this model and potential progression to hypertensive cardiovascular disease.