脑动脉粥样硬化模型大鼠大脑中动脉的蠕变

Creep mechanical properties of middle cerebral artery in rat cerebral atherosclerosis models

背景:蠕变是生物材料黏弹性固体的表现形式之一,脑动脉硬化和脑出血的防治有必要了解脑动脉硬化大脑中动脉的蠕变力学特性。目的:比较正常和动脉粥样硬化动物模型大脑中动脉的蠕变力学特性,确定动脉粥样硬化对大脑中动脉蠕变特性的影响。方法:SD雄性大鼠随机分为两组,模型组肌注维生素D3+尼古丁灌胃+高脂饮食制备动脉粥样硬化模型,对照组正常饮食,4周后处死大鼠取大脑中动脉为标本试件。在日本岛津电子万能试验机上对正常和动脉粥样硬化动脉标本试样进行蠕变实验。蠕变实验的应力增加速度为0.01MPa/s。设定实验时间为7200s,采集100个数,以一元线性回归分析的方法处理实验数据,记录蠕变曲线和数据,以及应变与时间的变化规律。结果与结论:正常和动脉粥样硬化大鼠大脑中动脉蠕变最初600s变化较快,之后应变缓慢下降,正常动脉标本7200s蠕变量高于动脉粥样硬化动脉标本(50.38%,48.26%,P<0.05)。说明正常和动脉粥样硬化大鼠大脑中动脉具有不同的蠕变力学特性,提示蠕变曲线是以指数关系变化的,动脉粥样硬化对大脑中动脉蠕变特性具有一定影响。

BACKGROUND： Creep is a visco-elastic biological material form of solid performance. It is necessary to understand the creep mechanical properties of middle cerebral artery in prevention and treatment of cerebral arteriosclerosis and cerebral hemorrhage. OBJECTIVE： To compare the creep rheological properties of middle cerebral artery between the normal and atherosclerotic animal model, to identify the effects of atherosclerosis on the creep properties of middle cerebral artery. METHODS： Male SD rats were randomly divided into 2 groups, in the model group, rats were injected vitamin D3 ＋ nicotine ＋ high-fat diet fed to prepare atherosclerosis models; in the control group, rats were fed with normal diet. Rats were killed at 4 weeks and the middle cerebral artery specimens were obtained. The creep experiments were performed with electron Shimadzu universal testing machine. The stress rate was 0.01 MPa/s, with 7 200 s experimental time. A total of 100 numbers were collected and analyzed using one linear regression analysis. The creep curve, as well as the variation of strain and time was recorded. RESULTS AND CONCLUSION： The middle cerebral artery creep changed faster at the initial 600 s in the normal and atherosclerotic rats, and then slowly decreased. The creep of normal rats were greater than that of the atherosclerotic artery specimens at the 7 200 s （50.38%, 48.26%, P〈0.05）. The results demonstrated that the middle cerebral artery have different mechanical properties of creep in normal and atherosclerotic rats. The creep curve is changed in an exponential relationship, and the atherosclerosis has certain effect on the creep characteristics of middle cerebral artery.