Objective To observe the effects of different shear stresses on the morphological changes of cochlear and brain microvascular endothelial cells from guinea pigs. Methods We obtained the morphological photos of cochlear and brain microvascular endothelial monolayer cells with the hydrodynamic system we designed and detected the morphological parameters such as Pyx. Results After digestion with collagenase type I

we obtained the monolayer cells of cochlear and brain microvascular endothelial monolayer. As to cochlear microvascular endothelial cells isolated from guinea pigs

no morphological changes were found when shear stress was 0.883 dyn/cm

2

and the acting time was 24 h. When shear stress was 1.184 dyn/cm

2

and the acting time was 8 h

compliant changes from former disorderliness into orderliness following the direction of liquid flowing in the cells occurred. This changing tendency was in a timedependent manner. As to brain microvascular endothelial cells

no morphological changes were found when shear stress was 0.267 dyn/cm

2

and the acting time was 24 h. When shear stress was 1.069 dyn/cm

2

and the acting time was 4 h

compliant changes began from former disorderliness into orderliness following the direction of liquid flowing in the cells. Conclusion Cochlear and brain microvascular endothelial cells from guinea pigs cultured under the condition of shear stress are morphologically different from statically cultured endothelial cells. Range of shear stress that two kinds of microvascular endothelial cells can tolerate is different.