放射治療已被發現會抑制紅血球之分化，先前的研究中，發現含矽顆粒可減少幹細胞在輻射暴露下的傷害； 然而，含矽顆粒對於紅血球生成之生物效應則尚未了解。本研究取人類單核球細胞(THP-1)與紅白血病細胞株 (HEL-92)，評估矽膠顆粒對紅血球分化之效應。實驗上以MTT 法分析矽膠顆粒的細胞毒性，以安全劑量之矽膠 探討其對紅血球細胞標示物血型糖蛋白A (glycophorin A) 表現之影響及其對細胞中活性氧化物生成之效應。在紅 血球生成試驗中，將HEL-92 細胞以THP-1 細胞之條件培養液培養，THP-1 細胞條件培養液分成對照組、輻射照 射組(5 Gy)、矽膠顆粒處理組、輻射照射(5 Gy)合併矽膠顆粒處理組等四組，評估其紅血球生成作用。此外，為 探討矽膠顆粒在細胞中所誘發的活性氧化物對紅血球生成的影響，本研究使用抗氧化物N-acetyl-l-cysteine (NAC) 探討其對活性氧化物及glycophorin A 之效應。將THP-1 細胞直接以矽膠顆粒處理或預先以NAC 先處理再加入矽 膠顆粒培養細胞，分析THP-1 的活性氧化物(ROS)生成及HEL-92 的glycophorin A 表現。結果顯示，輻射會抑制 紅血球分化，而矽膠顆粒則會刺激紅血球分化。此外，細胞中ROS 的生成量及紅血球分化數目皆較對照组高， 然而，此效應會被NAC 所抑制。由上述結果推測，矽顆粒可能是藉由增加細胞中活性氧化物與glycophorin A 的 生成提升輻射暴露下紅血球生成之防護作用。

Erythrocyte differentiation has been found inhibited during radiotherapy. In our previous study, silica materials were found able to decrease the damage of stem cells exposed to radiation; however, the bioeffects of silica materials on erythrogenesis of stem cells are still unknown. In this study, THP-1 cells (a human monocyte cell line) and HEL-92 cells (a human erythroleukemia cell line) were cultured to evaluate the effect of silica materials on the differentiation of erythrocytes. The cytoxicity of silica materials was evaluated by MTT assay. Safe dose of silica particles were added into the culture medium to investigate the effect on the expression of glycophorin A (an erythroid marker) in HEL-92 cells as well as the production of reactive oxygen species (ROS) in THP-1 cells. In erythrogenesis test, the HEL-92 cells were cultured with the conditioned medium obtained from THP-1 cells. The THP-1 conditioned medium was divided into four groups, including the control, radiation treatment (5 Gy), silica-material treatment and a combinative treatment of radiation and silica material. To investigate the effect of ROS induced by silica material on erythrogenesis, an antioxidant, N-acetyl-l-cysteine (NAC), was used to probe its effect on ROS and glycophorin A. The THP-1 cells were either exposed to silica particles or pretreated with N-acetyl-L-cysteine (NAC) 1 h prior to expose to silica particles. Analysis of the expression of ROS in THP-1 cells and glycophorin A in HEL-92 cells were then carried out. The results showed that radiation can inhibit the differentiation of erythrocytes, and the differentiation of erythrocytes was increased with silica materials particles. In addition, the ROS expression in THP-1 cells and the glycophorin A in HEL-92 cells were higher than the control group. However, the effects were inhibited by NAC pretreatment. The present results indicated that silica materials particles can stimulate stem cells to differentiate erythrocytes to decrease the injury of radiation possibly via increasing the level of ROS and glycophorin A expression within cells.