不同切应力下的内皮细胞条件培养基对平滑肌细胞增殖和胶原合成的影响

Effect of Supernatant of Endothelial Cells Exposed to Laminar Flow on Small Muscle Cells Proliferation and Collagen Synthesis

为研究不同切应力下内皮细胞条件培养基对平滑肌细胞和胶原合成的影响 ,建立平行平板流动腔模型 ,模拟产生定常层流 ,采用3H -胸腺嘧啶核苷掺入法和胃蛋白酶消化法 ,测定细胞DNA和胶原合成量。实验发现 ,与单用 10 %牛血清DMEM培养基比较 ,静态培养的内皮细胞条件培养基促使平滑肌细胞DNA和胶原合成 ,3H-胸腺嘧啶核苷掺入量从 749± 5 3cpm/ 10 3 细胞上升至 12 0 2± 6 3cpm/ 10 3(P <0 .0 1) ,平滑肌细胞掺入 2 ,3- 3H -羟脯氨酸量从 30± 6cpm/ 10 3 细胞上升至 47± 4cpm/ 10 3 细胞 (P <0 .0 1)。内皮细胞在 10和 2 5dyn/cm2 切应力剪切 18h后 ,内皮细胞条件培养基对平滑肌细胞DNA和胶原合成促进效应分别下降了 10 .41%± 5 .6 6 %、2 3.97%± 6 .2 3 %和 45 .71%± 2 .93%、6 4.5 3%± 2 .42 %。由此提示内皮细胞所受血流切应力减小后 ,其条件培养基能促使平滑肌细胞的增殖和胶原合成。

Aim [WT5”BZ]To establish whether the changes of local blood flow involved in the vessel wall remodeling, we investigated the effects of culture medium conditioned with endothelial cells exposed to hemodynamic shear forces on modulation of smooth muscle cells(SMC) proliferation and collagen synthesis. Methods SMC were isolated and cultured with collagenase digestion. Confluent monolayers of EC were exposed to static or to laminar flow conditions for 24 h using a parallel-plated flow chamber. Endothelial cell-conditioned medium was used to study the growth of PASMC by 3 H-thymidine uptake and collagen synthesis of PASMC using 2,3- 3 H-proline incorporation into 3 H hydroxyproline. Results The proliferative response of SMC to culture medium from endothelial cells under static flow is higher than to fresh medium(1 202±63 cpm/10 3 cells vs. 749±53 cpm/103 cells, P<0.01). SMC synthesized more collagen cultured with medium from endothelial cells under static flow than fresh medium(47±4 cpm/10 3cells vs. 30±6 cpm/10 3 cells, P<0.01). In contrast, medium conditioned with endothelial cells exposed to shear stress of 10 dyn/cm 2 and 25 dyn/cm 2 after 18 h reduced SMC DNA and collagen synthesis by 10.41%±5.66%, 23.97%±6.23% and 45.71%±2.93%, 64.53±2.42% comparison with medium from endothelial cells under static flow. Conclusions Our experimental results showed lower shear stress led to enhance the underlying SMC proliferation and collagen synthesis. It suggests a steady level of shear stress acting on artery plays an important role of preventing it of remodeling.