本研究將探討在不同強度(0-2 mW/cm2)及波長[blue (470 nm), green (525 nm), yellow (600 nm), and red (630 nm)]的發光二極體LED光照射下，對於羊水幹細胞前驅性基因(Oct-4, Sox2, and Nanog)以及成骨分化能力的影響。研究結果顯示，經過24小時LED可見光的照射，可以有效的增加羊水幹細胞前驅性基因的表現量。綠色光源的照射跟紅光、黃光、藍光比較起來，對於羊水幹細胞前驅性基因表現量有著非常顯著的提升。綠光跟藍光的照射，對於羊水幹細胞的成骨分化能力更有顯著提升的效果，但紅光跟黃光的照射並沒有太大的提升。此外本研究也對此可見光的效益成因做了探討，結果指出可見光促進羊水幹細胞成骨分化的原因並不是因為活性氧自由基的產生所造成。當在分化培養液中加入活性氧自由基抑制劑後，Alkali phosphatase activity(成骨分化的前段Marker) 以及Osteopontin(成骨分化的後段Marker)基因表現並沒有太顯著的改變。因此可以聯想到細胞如羊水幹細胞在可見光的影響下，在細胞上可能存在光接受器(light receptor)且在光照射後在基因表現上會有訊息的傳遞。 The effect of visible light irradiation on the expression of pluripotent genes (Oct-4, Sox2, and Nanog) in amniotic fluid-derived stem cells (AFSCs) and on the osteogenic differentiation ability of AFSCs was investigated using light emitting diodes (LEDs) at 0-2 mW/cm2 in various wavelengths [blue (470 nm), green (525 nm), yellow (600 nm), and red (630 nm)]. Pluripotent gene expression in AFSCs was up-regulated by visible light irradiation from a LED for 24 hours. Green light irradiation of AFSCs upregulated the expression of pluripotent genes more significantly than irradiation with blue, yellow or red light. The osteogenic differentiation of AFSCs was facilitated by green and blue light irradiation, but was not significantly facilitated by red or yellow light. Facilitated differentiation into osteoblasts by visible light irradiation was not mediated by reactive oxygen species (ROS); alkali phosphatase activity (a marker of early osteogenic differentiation) and gene expression of osteopontin (a marker of late osteogenic differentiation) did not change significantly between AFSCs in differentiation medium with or without a ROS scavenger (vitamin C). The mitogen-activated protein kinase/extracellular signal-regulated protein kinase (MAPK/ERK) pathway, as well as other unknown signaling pathways, may be responsible for the activation of signaling pathways that facilitate the differentiation of AFSCs into osteoblasts upon light irradiation.
