Comparative Analysis of Mechanical Properties of PWV, NO and Ascending Aorta between WHY Rats and SHR Rats.

BACKGROUND The aim of this study was to compare and analyze the tensile mechanical properties of the ascending aorta (AA) in Wistar Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs), for the purpose of providing a biomechanical basis for hypertension prevention. METHODS Pulse wave velocities (PWV) and serum nitric oxide (NO) concentrations were determined in 6-month-old WKY rats and SHRs (n = 21, n = 21, respectively). Then, 20 AAs from each group were obtained for longitudinal tensile testing. RESULTS The maximum stress, maximum strain, and strain at a tensile stress of 16 Kpa were greater in WKY rats than in SHRs (p < 0.05). The aortic elastic modulus and PWV value were greater in SHRs than in WKY rats (p < 0.05 for both), while NO concentrations were lower in the SHR group than in the WKY group (p < 0.05). CONCLUSIONS The AA tensile mechanical properties differed between the WKY rats and SHRs, and the tensile mechanical properties of the SHR model had changed. KEY WORDS Ascending aorta; Hypertension; Mechanical properties; Pulse wave velocity; SHR rats; WKY rats.