ABSTRACT
Differentiation of bone marrow mesenchymal stem cells (BMSCs) co-cultured with endothelial cells (ECs) under shear stress was studied. BMSCs and ECs were co-cultured on the two sides of PET membrane, and 20 dyn/cm2 shear stress produced by parallel plate flow chamber was performed after 72 hours. Cell morphology was observed under phase-difference microscope, and the expressions of smooth muscle-alpha-actin (SM-alpha-actin), calponin and smooth muscle myosin heavy chain (SMMHC) of BMSCs were detected by fluorescence immunocytochemistry. The co-cultured BMSCs became smooth muscle-like cells gradually; after 24 hours, the BMSCs started to express SM-alpha-actin. After 48 hours, they expressed SM-alpha-actin and calponin obviously. After 72 hours, obvious expressions of SM-alpha-actin and calponin, but not of SMMHC, were detected. Further static co-culture had no effect on SM-alpha-actin, calponin and SMMH expression of BMSCs; after 24 hours, shear stress induced feeble expression of SM-alpha-actin and obvious expression of SMMHC in co-cultured BMSCs, but it had no effect on the expression of calponin. The results suggest that shear stress may potentiate the differentiation of BMSCs (co-cultured with ECs) into mature smooth muscle-like cells.