兔脂肪干细胞复合PLGA支架的生物相容性研究

背景种子细胞和支架材料是角膜组织工程研究的主要课题。脂肪干细胞具有来源广泛、增生和分化能力强的特点而成为目前组织工程种子细胞的研究热点，聚羟基乙醇（PLGA）作为高分子可降解支架材料已成功用于构建多种组织器官。目的探讨兔脂肪干细胞的生物学特性及其复合多孔支架材料聚羟基乙醇（PLGA）的生物相容性，为进一步构建脂肪干细胞组织工程化角膜基质提供实验基础。方法取雌性新西兰大白兔颈背部脂肪组织，采用消化法分离培养兔脂肪细胞，传至第4代。将传代细胞分别以3×10^4／cm^2、3×10^4／cm^2、3×10^6／cm^2的密度接种于6孔板中，分别用成骨诱导培养液、成脂诱导培养液及成软骨诱导液进行诱导培养，并分别以质量分数1％茜素红-Tris-盐酸溶液、质量分数0．6％油红染液和免疫荧光法鉴定培养细胞的多向分化能力。将第4代细胞用稀释的DiO荧光染液重悬的脂肪干细胞按1×10^7／ml的密度接种于自制的多孔PLGA支架形成细胞-生物材料复合物，Hoechst法定量检测细胞在支架上的生长情况，并分别于接种后第1、3、7天对细胞-生物材料复合物行共焦显微镜和扫描电子显微镜检测，观察细胞在该支架上的黏附生长和基质分泌情况，评价PLGA的生物相容性。结果原代培养的脂肪细胞7～8d后可达80％～90％融合，呈成纤维细胞样外观。传代第4代的细胞成骨诱导2周后茜素红染色显示矿化结节及周围细胞着深红色；成脂诱导2周后油红0染色显示细胞质内布满红色脂滴颗粒；微团培养成软骨诱导2周后，免疫荧光染色结果显示Ⅱ型胶原表达阳性。细胞接种至PLGA支架材料第7天增生达到高峰期，扫描电子显微镜和共焦显微镜检测显示细胞在支架上贴附生长良好，能够在支架表面及孔隙内壁得到充分伸展和生长，细胞外基质分泌旺盛。结论培养的兔脂肪细胞具有脂肪干细胞的多向分化功能，与多孔PLGA支架复合具有良好的生物相容性，可作为构建组织工程化角膜基质的种子细胞和支架材料。

Biocompatibility of rabbit adipose-derived stem cells with porous polylactic-co-glycolic acid scaffold

Background Seed cells and scaffold material are the important aspects of corneal tissue engineering research.Adipose-derived stem cells(ASCs) are becoming the focus of seed cells research because of their wide source,powerful proliferation and differentiation abilities.As biodegradable polymer,polylactic-co-glycolic acid(PLGA) has successfully build multiple tissues and organs.Objective Present study was to ascertain the biological characteristics of the rabbit ASCs and their biocompatibility with PLGA scaffold in vitro and to provide groundwork for further study on the reconstruction of tissue engineered corneal stroma.Methods Adipose cells were isolated from lipoaspirate of New Zealand white rabbit using collagenase Ι.The cells were cultured and passaged.The generation 4 cells were inoculated to culture plate with 6 holes at the density of 3×104/cm2,3×104/cm2,3×106/cm2 respectively and cultivated in ossification inducing medium,lipoblast inducing medium and chondroblast inducing medium to identify the characteristics of the cells.The multilineage differentiated cells were identified by alizarin red staining,oil red O staining and immunoinfluorescene technique.The generation 4 cells were re-suspended with DiO influorescence fluid at the density of 1×107/ml and seeded on PLGA scaffold to fabricate cell-PLGA constructs.Quantitative analysis of cell proliferation on PLGA was detected by Hoechst DNA assay.The attachment and growth of adipose-derived stem cells on the scaffold were observed under the scanning electron microscope(SEM) and confocal microscopy in 1 day,3,7 days after seeding for the evaluation of biocompatibility between cells and PLGA.Results Primarily cultured cells reached 80%-90% confluence after 7-8 days with the fibroblast-like appearance.Adipose-derived stem cells of rabbits differentiated into osteoblast,adipocyte and chondroblast successfully,showing the positive stain for alizarin red staining,oil red O staining and immunoinfluorescene technique respectively.Proliferation of cells on PLGA scaffold went into plateau phase at 7 days after culture.SEM and confocal microscopy revealed the well-attached,spread cells along the scaffold and abundant excellular matrix both on the surface and interior pore of scaffold.Conclusion Cultured rabbit adipose cells have the ability of potential multilineage differentiation and good biocompatibility with PLGA scaffold,which could be used to construction of tissue engineered corneal stroma.