Abstract
The objective of our research was to reveal the effects of different shear stresses on the expression of proto‐oncogenes c‐fos and c‐myc in cultured human umbilical vein endothelial cells (HUVEC). A parallel plate flow chamber was used to control the value and duration of shear stress (SS), and the expression of c‐fos and c‐myc protein was measured by immunocytochemistry methods and image analysis software. Some important conclusions were drawn. In the stationary state, c‐fos protein levels were very low. The SS's of 4 dyn/cm2 and 10 dyn/cm2 induced rapid increases of c‐fos protein levels, especially the SS of 10 dyn/cm2. The levels peaked at 1.0 h. Then, c‐fos protein levels began to decrease, after 2.5 h, they declined to almost basal levels. In the stationary state, the c‐myc protein levels were also very low slowly increasing after the onset of shear stress. The effects of 4 dyn/cm2 and 10 dyn/cm2 SS on c‐myc protein expression levels had no difference and apparently were less than the effect on c‐fos protein levels. The c‐myc protein levels peaked at 1.5 h. Subsequently, they fell to basal levels at 2.5 h. Increased expression of these proto‐oncogenes mediated by shear stress may have important effects on the regulation of critical cell activities, such as proliferation and differentiation.