| Summary: | 碩士 === 國防醫學院 === 生理學研究所 === 101 === Vascular fluid shear stress had always existed and played an important role in regulating vascular endothelial cells (ECs) and smooth muscle cells (SMCs) functions. High glucose (HG) and excessive free fatty acid (FFA) are well-known risk factors of ECs dysfunction and atherosclerosis. However, the effects of ECs response to shear stress and that of underlying SMC under HG plus FFA is still unclear. EC and SMC co-culture was established by plating cells on the opposite sides of a 10-m-thick membrane containing 0.4-um pores. Human aortic endothelial cells (HAECs) were seeded onto the outer side of the membrane, and the opposite (inner) side of the membrane was seeded with human aortic smooth muscle cells (HASMCs) to form EC/SMC co-culture. ECs were exposed to high shear stress (12 dyne/cm2; HSS), low shear stress (0.5 dyne/cm2; LSS), or a static condition for 8 (short term) or 20 (long term) hours. In addition, high glucose (25 mM; HG) and palmitic acid (300 uM; PA) were treated individually or in combination (HG + PA) in combination with shear stress treatment or static condition. The results showed that when HSS applied to co-cultured EC, expression of vaso-protective proteins such as heme oxygenase-1 (HO-1) in both co-cultured ECs and SMCs would be induced in both short term and long term experiments, even if co-cultured ECs were treated with HG and PA individually or in combination. But, HSS induced phosphorylation of adenosine monophosphate activated protein kinase (AMPK) in co-cultured ECs was abolished in short term experiment when co-cultured ECs were treated with HG and PA in combination. We also used AMPK specific siRNA to evaluate and prove that HSS induced HO-1 in co-cultured ECs is going through AMPK independent pathway. In addition, when HSS applied to co-cultured ECs, the proliferating cell nuclear antigen (PCNA) expression of opposite SMCs was down regulated. But, the significance of PCNA down-regulation in SMCs was abolished when co-cultured ECs were treated with HG and PA individually or in combination. Our findings provide new aspect for elucidating how high shear stress provides possible protections of vascular functions such increasing HO-1 expression of ECs and SMCs in early stages of diabetes induced atherosclerosis with hyperlipidemia.
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