Different Effects of Orbital Shear Stress on Vascular Endothelial Cells: Comparison with the Results of In Vivo Study with Rats

PURPOSE An attempt was made to characterize the orbital shear stress by comparing the effects of orbital shear stress on vascular endothelial cells (ECs) with the results of animal experiments. MATERIALS AND METHODS In the laboratory study, cultured ECs of well were distinguished by center and periphery then exposed to orbital shear stress using an orbital shaker. In the animal study, arteriovenous (AV) fistulas were made at the right femoral arteries of Sprague-Dawley rats to increase the effect of the laminar flow. The condition of the stenosis was given on the left femoral arteries. The protein expression of inducible nitric oxide synthase (iNOS) and Akt phosphorylation were observed and compared. RESULTS Under orbital shear stress, ECs showed an increase in iNOS protein expression and phosphorylation of Akt but most of the protein expressions derived from the periphery. When compared to the animal study, the increased expression of iNOS protein and phosphorylation of Akt were observed in the sample of AV fistula conditions and the iNOS protein expression was decreased in the stenosis conditions. CONCLUSION Orbital shear stress did not show the characteristics of a pure turbulent shear force. By comparing the observation with the morphological changes of vascular ECs and site-specific protein expression on the results of animal experiments, uniform directional lamina shear stress forces were expressed at the periphery.