Abstract: Objective To investigate the morphological effect of fluid shear stress on pig iliac endothelium cells cultured solely or co-cultured with pig small intestinal submucosa.Methods The shear stress of 40×10^-5 N/cm² were carried out for 12 h on both groups.The images were recorded every 30 min.The directional angles were calculated.Results In the group of cell cultured solely:The defluvium of cells was obvious at the 1st hour,but the shape of cells didn't change.At the 4th hour,the defluvium of cells was little,the cell became round from its initiatory polygon shape.At the 8th hour,the defluvium of cell could not be observed.The shape of cells became fusiform and gracile.The cells arranged along the direction of flow field in the local area.At the 12th hour,the cells became more and more gracile.The trend of realignment of cells along the direction of flow field was obviously.The directional angles of cells at the 12th hour was significantly different from the zero hour.In the group of cell co-cultured with small intestinal submucosa:At the 1st hour,some of cells were brushed off mildly.The defluvium of cells could not been observed since the 2nd hour.The directional angles didn't change significantly in the 12 hours.Conclusion The shear stress of 40×10^-55 N/cm² cannot influence the cell of co-cultured but do influence the cell cultured solely.

Key words: shear stress, small intestinal submucosa, endothelium cells, tissue engineering