Effect Of Shear Stress On Rat Brain Microvascular Endothelial Cells Cytoskeleton Proteins And Adhesion Molecule

To provide the relevant experiment data to the current understanding of basic mechanisms that explain the signal transudation pathway occurring inside the endothelial cells under the effect of SS, we use flowing chamber method to exert SS on Rat Brain Microvascular Endothelial Cells. With the aid of immunostaining, histochemistry and computer image processing method, the specific expression rule of cytoskeleton and ICAM-1 is studied. Our study provides meaningful clue for the role of SS played in pathogeny of atherosclerosis and thrombosis. We found that compared with control, the F-actin content of cell cytoskeleton under the effect of one- way flow raised significantly. The bundles of stress fiber appeared in cells, while the two-way flow having no such effect. After exertion of cytochalasin, both one-way flow and two-way flow had little effect on F-actin content of cell cytoskeleton and the number of dead and missing cells raised. In ICAM-l study, we found that differ from endothelial cells of other species or vascular beds, RBMECs demonstrated a specific upregulation in ICAM-l expression. Expression of ICAM-l is increased O.5h after the onset of SS. The expression reached its highest level 4 hours after onset of SS, then declines after that. The expression of ICAM-l is not force-dependent. While Tsuboi found the expression of ICAM-l on human umbilical vein endothelial cells (HUVECs) was that lh after onset of SS (1 5dynlcm2), the expression of ICAM- 1 increased significantly and reached its highest level 8 hours after onset of SS. The initial increase and the peak of ICAM-l expression on RMBECs all appear earlier that those on HUVECs. This is probably due to the sensitivity of RMBECs to SS so that the small magnitude of SS is large enough to initiate the signal transduction pathway of ICAM- 1 expression. We also found that supematants of RBMECs exposed to SS can not significantly influence the ICAM- 1 expression of RBMECs, indicating that the changes in ICAM- 1 3 expression is possibly the direct effect of SS on endothelial cells, and nOt by factorsreleased by endothelial cells under SS.