大鼠脂肪干细胞复合胶原-壳聚糖-硫酸软骨素三维支架构建组织工程软骨

目的 探讨大鼠脂肪干细胞复合胶原-壳聚糖-硫酸软骨素三维支架的优越性.方法 选用6周龄健康Wistar大鼠,分离出脂肪干细胞后行体外培养.将Ⅰ型胶原溶液与壳聚糖溶液混合后冷冻干燥,交联硫酸软骨素后再冷冻干燥得到复合三维支架,检测支架的孔径值、含水量及孔隙率.将接种的脂肪干细胞消化后分别接种到平面、微球和支架,软骨方向诱导培养.MTT检测细胞增殖情况,3周后倒置显微镜及扫描电镜观察细胞形态及在支架上的生长及黏附情况,并分析成软骨分化的情况.结果 5 d后MTT检测显示三维支架组及微球组细胞增殖速度较平面组快;三维支架组14 d后仍有细胞增殖.组织学分析显示细胞在支架上密集重叠生长,内层仍有残留支架结构.Ⅱ型胶原免疫组化检测结果显示,三维支架组及微球组表达呈强阳性,而平面组表达呈弱阳性.RT-PCR结果显示各组均有软骨特异性mRNA的表达.但平面组一直表达X型胶原,微球组培养至21 d时也表达X型胶原,而三维支架组则一直未表达.结论 复合胶原-壳聚糖-硫酸软骨素三维支架能促进细胞的增殖、分化,并能更好地维持软骨细胞的表型,可以作为组织工程构建软骨的最佳选择.

Cartilage tissue engineering by collagen-chitosan-chondroitin sulfate scaffold seeded with rat adipose tissue-derived stromal cells in vitro

Objective To evaluate the character of the collagen-chitosan-chondroitin sulfate scaffold seeded with rat adipose tissue-derived stromal cells. Methods A dipose tissue were harvested from 6 weeks old Wistar rats and the stromal cells were harvested by type Ⅰ collagenase and then cultured in vitro. Type Ⅰ collagen was fully mixed with chitosan, freeze-dried and cross-linked with chondroitin sulfate, then freeze-dried again and sterilized by ethylene oxide. The pore diameter, water content, porosity of the scaffold were tested. The adipose tissue-derived stromal cells were digested, seeded into the plates, scaffold, and cen-trifuged into pellet, and then induced into cartilage. MTT detection for cell proliferation was done. After 3 weeks, the cell morphology, and cell proliferation and adhesion were observed, and chondrngenic differenti-ation was also analyzed. Results The pore diameter, water content, porosity tested for the scaffold showed an appropriate form. Cell proliferation showed faster in the scaffold and pellet culture system after 5 day, there was still cell proliferation in the scaffold system after 14 days but no obvious changes in the pellet cul-ture system; ceils on the scaffold proliferated densely showed by histological staining, but there was a scaf-fold structure residues in the inner layer. The finding of type Ⅱ immunohistochemistry stain showed that cells express strong positive for type Ⅱ collagen in the scaffold and pellet culture system whereas it was weakly positive in the plate culture system; the specific mRNA for cartilage, type Ⅱ collagen, aggrecan and SOX-9 were expressed in all three systems showed by RT-PCR, but type X collagen was expressed continu-ously in the plate culture system and expressed after 21 days in the pellet culture system, whereas it was not detected in the collagen-chitosan-chondroitin sulfate scaffold system. Conclusion The parameters of the collagen-chitosan-chondroitin sulfate scaffold were suitable in our study. The results suggested that it can promote the adipose tissue-derived stromal cells proliferation and chondrogenic differentiation better than the plate and pellet culture systems and maintain the phenotype of chondrocytes well; it is the optimal choice for cartilage tissue engineering in the future.