目的：以人脂肪来源干细胞（human adipose-derived stem cells，hASCs）作为种子细胞，通过三维生物打印构建hASCs共混物打印体，以低能量激光为刺激手段，探索低能量激光照射（low level laser irradiation，LLLI）对三维结构成骨能力的影响。方法：制备hASCs/海藻酸钠/明胶三维生物打印体，并随机分为4组：增殖培养基（proliferative medium，PM)组、PM+LLLI组、成骨培养基（osteogenic medium，OM）组、OM+LLLI组，激光照射总能量密度为4 J/cm2。通过肉眼及倒置相差显微镜对打印体进行观察并拍照；用Live/Dead染色评价打印体内细胞存活率；利用免疫荧光染色比较各组成骨向分化因子骨钙素（osteocalcin，OCN）及 Runt相关转录因子2（Runtrelated transcription factor 2，Runx2）的表达。结果：获得规格10 mm×10 mm×1.5 mm、半透明、网格状的三维结构体，微丝宽度约为1 mm，孔隙呈圆形，直径在700 μm左右。打印体内细胞存活率较高，且各组间无明显差异。第7天时，OCN的表达量从高到低依次为OM+LLLI组、PM+LLLI组、OM组、PM组，除PM+LLLI组与OM组间差异无统计学意义外，其他各组间差异均有统计学意义（P<0.01）。到了第14天时，各组OCN表达量较第7天均有不同程度增高，OM+LLLI与OM组间差异不再有统计学意义。Runx2表达量方面，OM+LLLI组在第7天时即达到90%以上，显著高于OM组（P<0.01），PM+LLLI 组也显著高于PM组（P<0.05）；而到第14天，PM+LLLI组及OM+LLLI组的Runx2表达量又明显降低至低于相应未照射组。故OCN及Runx2表达量上，成骨诱导培养组明显高于未成骨诱导组，经低能量激光照射组明显高于未照射组，随着培养时间的延长，这种差异逐渐减小。结论：LLLI不会对hASCs/海藻酸钠/明胶三维生物打印体内hASCs存活率造成影响，且可促进hASCs成骨向分化。

Objective： To explore the effects of low level laser irradiation (LLLI) on the osteogenic capacity of three-dimensional （3D） structure by 3D bio-printing construct used human adipose-derived stem cells (hASCs) as seed cells. Methods: Using hASCs as seed cells, we prepared sodium alginate/gelatin/hASCs 3D bio-printing construct, and divided them into four groups: PM (proliferative medium), PM+LLLI, OM (osteogenic medium) and OM+LLLI, and the total doses of LLLI was 4 J/cm2. Immunofluorescence microscopy was used to observe the viability of the cells, and analyze the expression of the osteogenesis-related protein Runt-related transcription factor 2 (Runx2) and osteocalcin (OCN). Results: The 3D constructs obtained by printing were examined by microscope. The sizes of these 3D constructs were 10 mm×10 mm×1.5 mm. The wall thickness of the printed gelatin mold was approximately 1 mm, and the pores were round and had a diameter of about 700 μm. The cell viability of sodium alginate/gelatin/hASCs 3D bio-printing construct was high, and the difference among the four groups was not significant. On day 7, the expression of OCN from high to low was group OM+LLLI, PM+LLLI, OM and PM. There were significant differences among these groups (P<0.01), but there was no significant difference between group PM+LLLI and OM. On day 14, the expression of OCN in each group was hi-gher than that on day 7, and there was no significant difference between group OM+LLLI and OM. The expression of Runx2 in group OM+LLLI was more than 90%, significantly higher than that in group OM (P<0.01). But the expression of Runx2 in group PM+LLLI and OM+LLLI were significantly lower than that in the non-irradiated groups. The expression of osteogenesis-related protein Runx2 and OCN were higher in OM groups than in PM groups. Furthermore, the irradiated groups were significantly higher than the non-irradiated groups. Conclusion: LLLI does not affect the cell viability of sodium alginate/gelatin/hASCs 3D bio-printing construct, and may promote the osteogenic differentiation of hASCs.