1.Pressurizing and Stretching Experiment in Arterialized Veins of Rabbits
Yuhao ZHANG ; Pei NIU ; Zhimin ZHANG ; Xiaolong NIU ; Wenzeng SHEN ; Liangchao HAO ; Yujuan ZHOU ; Fulin IU
Journal of Medical Biomechanics 2020;35(2):E156-E162
Objective To establish the model of rabbit vena arterialization, so as to investigate the difference of mechanical parameters between arteries and veins as well as before and after arterialization. Methods Twenty-four rabbits were randomly divided into experimental group (n=12) and control group (n=12). By establishing the rabbit vena arterialization model for experimental group, the arterial blood could flow into the veins. After model creation, the vein would be removed 4 weeks after surgery. In the meantime, the external jugular veins and cephalic arteries extracted from control group were acquired. Compressive pressurizing and stretching tests on all vessels were conducted at the same time(including arteries, veins and arterialized veins). Observation was supported by HE staining and immune tissue chemical techniques. Results There were no deaths among the 24 rabbits, with unobstructed blood flow in veins. With the increase of intravascular pressure, the outer diameter of veins changed at first and then stabilized at a fixed value. The elasticity of veins was worse than that of arteries. The external diameter of veins increased rapidly with internal pressure of veins increasing and reached its extreme elasticity. Comparatively, the elasticity of arteries increased slowly. HE staining results showed that thickness of the vascular wall was thinner, while it became thicker after vena arterialization. After vena arterialization, proliferating cell nuclear antigen(PCNA) and α-actin showed positive results. It further proved that proliferation existed among smooth muscle cells, and veins showed the tendency of restenosis again. The elasticity of veins after transplantation into the arterial system was improved compared with that before transplantation. Conclusions Accompanied by the increasing pressure, the vein could reach its elasticity extremity faster than the artery. Under such a long-term high pressure, vein intima was vulnerable. After vena arterialization, with the gradual thickening of vein intima, the tendency of vessel restenosis was obvious, and the elasticity of veins has been improved after transplantation.