The Model Construction Of Atherosclerosis Caused By The Different Shear Stress In The Rabbit Carotid Artery

Background atherosclerosis (AS) has become a major disease suferring people's health.Acute cardiovascular disease and cerebrovascular disease are two common and multi-onset diseases, which have serious effects on the health of human beings, and their pathological basis is atherosclerosis (AS). Traditionally, the development of AS was thought to be a line procedure, during which lipid infiltrated into the intima of the vessel and plaques formatted blocked the vessel. So regression of the plaques was the main therapy strategy. However, recent studies show that plaque disruption and arterial thrombosis are recognized as critical to the onset of acute coronary syndromes (ACS) and a vulnerable plaque that is prone to rupture is vital to induce ACS. Studies show that a vulnerable plaque has (1) a thin fibrous cap;(2) a large lipid core;(3) many inflammatory cells such as macrophages infiltrated;(4) endothelial dysfunction;(5)progressive blood coagulation function Whether a plaque ruptures or not lies in two factors:the intrinsic factor-- tissue characteristic and the extrinsic factor-- tissue stress, and the former is decisive. Therefore, it is very significant to detect vulnerable plaques earlier and take effective interventions to prevent ACS. It is a logical way to research on the factors of vulnerability of plaques and take effective methods to prompt vulnerable plaques becoming stable.Objectives Using the arterial cannula in the rabbit carotid artery to explore the effect of the increased, lowered and oscillatory wall shear stress respectively in the progress of atherosclerosis. Methods According to the theory of hydromechanics, the rabbit atherosclerosis model was established by the arterial cannula developed by ourselves adding the high fat diet. The data was detected in three different time points, including the common carotid arterial intima-media thickness(IMT), end diastolic diameter(Dr), systolic peak velocity(Vs), dialstolic end velocity(Vd), mean velocity(Vm). And then, the shear stress was calculated. At the end of 12 weeks, arterial samples were collected after the rabbits were killed, and the pathological changes of common carotid artery were detected through hematoxylin and eosin stain, oil red o stain and massion stain.Results The levels of the increased and lowered shear stresses caused by the cannula are significantly different from the basic line(both P<0.05), and the vascular ultrasound showed there was chaotic blood flow in the area of oscillatory shear stresses. Compared to the area of oscillatory shear stresses, the one of the lowered shear stress had larger plaque, containing more lipids and more smooth muscle cells, but less collagen. There was no obvious plague in the area of increased shear stress.Conclusions The cannula in common carotid artery could induce different shear stresses—increased, lowered and oscillatory shear stress—in different segments of a straight artery. The increased shear stresses could inhibit atherosclerosis, while the lowered and oscillatory stress could induce its formation.