去甲肾上腺素对犬腹主动脉瘤的影响

The aim of this study is to investigate the effect of different doses of norepinephrine (norepinephrine, NE) on abdominal aortic aneurysm (abdominal aortic aneurysm, AAA) in dogs. Twelve healthy adult beagles, female, weighing (11 ± 1.5) kg, were randomly divided into four groups with three dogs in each group, the NE low-dose group (0.2 µg · kg⁻¹ · min⁻¹), NE medium-dose group (0.4 µg · kg⁻¹ · min⁻¹) and NE high-dose group (0.8 µg · kg⁻¹ · min⁻¹) were set up respectively, the control group was only given 60 mL of 5% glucose sodium chloride injection each time. The abdominal aorta was surgically separated and intubated,then the elastase was injected into the middle membrane of the abdominal aorta to form AAA. After the formation of AAA, different dosage of NE and 5% glucose sodium chloride injection were administered intravenously at a rate of 60 mL/h, one hour a day for two weeks. Blood pressure changes within the AAA was monitored by BL-420 N biological signal collector, changes of AAA diameter and blood flow velocity were monitored by B ultrasound, wall shear stress (WSS) changes of blood vessels were by computer numerical simulation; after 21 d of drug withdrawal, the experimental dogs were sacrificed, HE and EVG sections were stained to observe the changes of AAA morphology and cell composition. The results were as follows: the systolic blood pressure, diastolic blood pressure and mean arterial pressure of each group using NE were significantly increased compared with those before medication (P < 0.01), and the blood flow velocity was significantly or extremely significantly increased compared with those before medication (P < 0.05 or P < 0.01); the WSS at the AAA in the middle-dose and high-dose groups was significantly higher than that in the control and low-dose groups (P < 0.01); the amount of thrombus deposition, inflammatory cell infiltration, elastic fiber and elastic lamina damage in the control group were more serious than those in the groups using NE. The results indicated that the NE can effectively increase blood pressure and blood flow velocity in AAA and increase WSS, reduce intraluminal thrombosis, and will not cause AAA rupture within a certain dose range.