在傷口癒合的過程中，血管必須再生以輸送修復組織的養分來源和廢物代謝。欲將組織工程應用於傷口敷料，必須慎選血管的細胞來源與微環境成份以協助血管新生。本實驗萃取胎盤絨毛組織之間葉幹細胞作為內皮細胞分化的幹細胞來源，在分化前胎盤間葉幹細胞無表現KDR、VE-cadherin、CD31與vWF等內皮細胞標幟，經由含促進血管新生因子之培養液EGM-2或是基礎培養液DMEM-10% FBS培養至21天後，內皮標幟基因量均有上升的現象，並且同時觀察到內皮標幟蛋白的表現。在連續分化32天的試驗中，內皮標幟基因在14天至18天開始增加表現量，於第21天達到最高的基因量；同時結果顯示第七代幹細胞較第五代提早表現內皮基因，說明第七代細胞有較趨近於內皮細胞的特性。以低分子量4300 Da或高分子量1500 kDa透明質酸的各種濃度(10 μg/mL、100 μg/mL、1000 μg/mL)條件添加於DMEM-10% FBS中培養間葉幹細胞，觀察到4300 Da 10 μg/mL與1500 kDa 10/100/1000 μg/mL可促使部份內皮細胞標幟表現提升。根據以上結果，得知胎盤間葉幹細胞經由培養21天可以被誘導走向內皮細胞分化，並且添加特定條件之透明質酸可以促進幹細胞表現內皮細胞標幟，顯示這些透明質酸在內皮細胞分化中具有輔助的特性。

During wound healing, angiogenesis plays a key role in regeneration of new blood vessels for delivery of oxygen and nutrients to repairing site. How to choose an excellent cell source and components of microenvironment for angiogenesis is important in tissue engineering. We investigated the endothelial differentiation of placenta-derived mesenchymal stem cells (PDMSCs), a population of endothelial marker KDR/VE-cadherin/CD31/vWF-negative cells. PDMSCs, cultured in EGM-2 medium containing angiogenic growth factors or basal medium DMEM-10% FBS for 21 days, showed high expressions both in gene and protein levels of endothelial markers. The time course of endothelial differentiation from day 7 to day 32 for PDMSCs showed increased levels of mRNA encoding KDR, VE-cadherin, CD31, vWF and VEGF at day 14 or day 18, and reached the highest level at day 21. P7 expressed high level of mRNA earlier than P5 PDMSCs, indicating P7 PDMSCs had more potential of differentiation into endothelial cells (ECs). Addition of low molecular weight (4300 Da) or high molecular weight (1500 kDa) hyaluronan (HA) with concentration 10 μg/mL, 100 μg/mL and 1000 μg/mL to DMEM-10% FBS medium showed that expression of some endothelial markers were enhanced by 4300 Da 10 μg/mL and 1500 kDa 10/100/1000 μg/mL HA. In conclusion, these results suggest that PDMSCs cultured in DMEM-10% FBS medium for 21 days can be induced into endothelial differentiation, and HA promotes gene and protein expression of endothelial markers, demonstrating HA has angiogenic potential.

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