抄録
We evaluated a potential of a high-frequency ultrasonography (US) system (Vevo770) in the continuous noninvasive observation of a development of aneurysm using vascular injury model induced by angiotensin II (AngII).Twenty-five male apoE-/- mice at 8 weeks of age were used. Over 4 weeks, mice fed on a high fat diet received AngII(1.44 mg/kg/day, SC). Blood pressure was monitored continually by a telemetry system. US examination was performed on the abdominal aorta(AA) and renal artery(RA). Assessment of vascular dilation and aneurysm was carried out with B-mode US. Assessment of blood flow velocity for evaluation of hemodynamic function was also performed using US pulsed-Doppler(PD). During the PD assessment, peak systolic and end-diastolic velocities(Vs, Vd) and resistive index(RI) were obtained. Pathological test was performed at the end of the experiment. AngII-induced vascular dilation was seen in the AA and RA by 164.39 % and 122.6 % respectively. From the 1st week of treatment, thoracic aortic aneurysm and abdominal aortic aneurysm showing severe vascular dilation of >200% were observed in 1 and 3 mice out of 15 mice, respectively. Thereafter, both aneurysms were diagnosed pathologically as dissecting aneurysms. Hemodynamic assessment showed increased RI and reduced Vs and Vd in the AA and RA. In conclusion, we could detect vascular remodeling, such as vascular dilation, hemodynamic dysfunction and aneurysms with the US. The high frequency US system is a valid method of vascular dysfunction assessment in noninvasive longitudinal rodent studies.
