Objective To observe the expression of integrin αVβ3 in vascular endothelium cultured in vitro at different time points under different level of shear stress. Methods（1）We established a vascular culture system in vitro which could provide steady flow with different level of shear stress, and tested the flow stability when loading different level of shear stress. （2） A total of 50 rabbits were randomly divided into low shear stress group （5 dyn/cm2, n=25）and normal shear stress group（20 dyn/cm2, n=25）. Rabbits in each group were further randomly divided into five different time points as 2 h, 4 h, 8 h, 16 h and 24 h（n=5 at each time point）. The descending aorta of rabbits were harvested and cultured in the vascular culture system in vitro under different level of shear stress. The expression sites and intensity of αVβ3-Integrin in vascular endothelium were examined at 5 different time points in both groups by immunohistochemical staining. Results The vascular culture system in vitro was stable in providing laminar flow with different level of shear stress required for the experiment. Vascular endothelium expressions of αVβ3-Integrin in the low shear stress group were in high level at all the 5 time points and reached its summit at 16 h, when the mean optical density（MOD）value was （1.995±0.194）×10-2. In the normal shear stress group, the MOD value decreased time-dependently at the 5 time points. The MOD values at 2 h （0.059±0.005）×10-2 and 4 h（0. 049±0.002）×10-2 were significantly higher than those at other time points （P＜ 0.05）. The αVβ3-Integrin MOD values of the low shear stress group were significantly higher than those of the normal shear stress group at all the 5 respective time points （P=0.000）. Conclusion Low shear stress can significantly promote the expression of αVβ3-Integrin while normal shear stress decreases the expression of αVβ3-Integrin in vascular endothelium cultured in vitro.
【Abstract】Objective To observe concentration changes of substances including hepatocyte growth factor(HGF),interleukin-6(IL-6),nitric oxide(NO),nitric oxide synthase(NOS) that were secreted by sinusoidal endothelial cells(SECs) in different shear stress and study the effects of shear stress on the secretions of SECs.Methods To establish a hemodynamics equipment and to set up a way to separate and culture SEC. The rats were divided into two groups: the control group (shear stress was 0 dyn/cm2) and study group. Study group was divided into three subgroups according to shear stress (12, 24 and 48 dyn/cm2). Sinusoidal endothelial cell culture mediums were examined in different shear stress and phases.Results HGF, IL-6, NO and NOS secreted by sinusoidal endothelial cells in different shear stress were distinctive and had positive correlation with shear stress and action time. Conclusion In vitro, the secretion of HGF,IL-6,NO and NOS of sinusoidal endothelial cells are increased along with shear stress rising, which suggests that the rising pressure in portal vein after hepatectomy may result in SECs activated．Activated SECs then secret many cytokines and medias to trigger the regeneration of liver.