三维动静态培养软骨源性微组织的细胞行为及软骨形成能力

Behavior of cartilage-derived microtissue and ability of cartilage formation in three-dimensional dynamic and static culture conditions

背景:与传统二维培养相比,三维培养软骨微组织具有更大的优势,但仍需进一步探索更有利的三维培养方式。目的:评价2种三维培养方式下微组织的细胞行为及促软骨形成能力。方法:通过化学脱细胞方法和组织粉碎方法制备软骨源性微载体,采用DNA定量和核染色验证脱细胞是否成功,通过组织学染色观察脱细胞前后基质保留情况,采用扫描电子显微镜和CCK-8方法对微载体进行表征;通过三维静态培养法和三维动态培养法将软骨源性微载体与人脂肪间充质干细胞结合构建软骨源性微组织,利用扫描电子显微镜、活死染色、RT-qPCR等手段检测两组微组织的细胞活力及成软骨能力。结果与结论:①成功制备软骨源性微载体,与脱细胞前相比,脱细胞后DNA含量显著降低(P<0.001);扫描电子显微镜观察微载体表面有胶原包绕,保持天然软骨细胞外基质特征;CCK-8法检测表明微载体无细胞毒性且能够促进细胞增殖;②扫描电子显微镜及活死染色结果显示,相比三维静态组,三维动态组微组织细胞具有更舒展的形态,细胞与细胞间、细胞与基质间、基质与基质间形成广泛的连接;③RT-qPCR结果表明两组微组织SOX9、蛋白聚糖、Ⅱ型胶原表达在培养7 d或14 d时均增高;14 d时三维动态组各基因相对表达量均显著高于三维静态组(P<0.05);21 d时三维静态组各基因表达均显著高于三维动态组(P<0.001);④结果表明,与三维静态培养微组织相比,三维动态培养微组织可在更短时间实现软骨相关基因的高表达,显示出更好的细胞活性和成软骨能力。

BACKGROUND:Compared with traditional two-dimensional culture,three-dimensional microtissue culture can show greater advantages.However,more favorable cultivation methods in three-dimensional culture still need to be further explored.OBJECTIVE:To evaluate the cell behavior of microtissue and its ability to promote cartilage formation under two three-dimensional culture methods.METHODS:Cartilage-derived microcarriers were prepared by chemical decellularization and tissue crushing.DNA quantification and nuclear staining were used to verify the success of decellularization,and histological staining was used to observe the matrix retention before and after decellularization.The microcarriers were characterized by scanning electron microscopy and CCK-8 assay.Cartilage-derived microtissues were constructed by combining cartilage-derived microcarriers with human adipose mesenchymal stem cells through three-dimensional static culture and three-dimensional dynamic culture methods.The cell viability and chondrogenic ability of the two groups of microtissues were detected by scanning electron microscopy,live and dead staining,and RT-qPCR.RESULTS AND CONCLUSION:(1)Cartilage-derived microcarriers were successfully prepared.Compared with before decellularization,the DNA content significantly decreased after decellularization(P<0.001).Scanning electron microscope observation showed that the surface of the microcarrier was surrounded by collagen,maintaining the characteristics of the natural extracellular matrix of cartilage cells.CCK-8 assay indicated that microcarriers had no cytotoxicity and could promote cell proliferation.(2)Scanning electron microscopy and live and dead staining results showed that compared with the three-dimensional static group,the three-dimensional dynamic group had a more extended morphology of microtissue cells,and extensive connections between cells and cells,between cells and matrix,and between matrix.(3)The results of RT-qPCR showed that the expressions of SOX9,proteoglycan,and type II collagen in microtissues of both groups were increased at 7 or 14 days.The relative expression levels of each gene in the three-dimensional dynamic group were significantly higher than those in the three-dimensional static group at 14 days(P<0.05).At 21 days,the three-dimensional static group had significantly higher gene expression compared with the three-diomensional dynamic group(P<0.001).(4)The results showed that compared with three-dimensional static culture microtissue,three-dimensional dynamic culture microtissue could achieve higher expression of chondrogen-related genes in a shorter time,showing better cell viability and chondrogenic ability.