Abstract:

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.