基质细胞衍生因子1修饰左旋聚乳酸多孔微球促进软骨细胞增殖和组织形成

Chondrocyte proliferation and tissue formation enhanced by stromal cell derived factor-1 modified poly-L-lactic acid porous microspheres

背景:二维培养条件下的软骨细胞增殖及表型维持受限,多孔微球作为支架材料可提供三维培养环境,以更好地模拟体内生长条件。基质细胞衍生因子1是有强趋化效力的稳态细胞因子,能够促进细胞的黏附与增殖。目的:明确接枝基质细胞衍生因子1左旋聚乳酸多孔微球对软骨细胞生物学特性及软骨组织形成的影响。方法:(1)体外验证不同质量浓度基质细胞衍生因子1对兔软骨细胞增殖、迁移、表型维持的影响。(2)采用复乳法制备左旋聚乳酸多孔微球,利用碳二亚胺法将基质细胞衍生因子1接枝于左旋聚乳酸多孔微球上,通过酶联免疫吸附实验及孵育基质细胞衍生因子1特异荧光抗体验证接枝情况。(3)将兔软骨细胞分别接种于左旋聚乳酸多孔微球、接枝基质细胞衍生因子1左旋聚乳酸多孔微球上,检测细胞增殖与黏附。(4)在裸鼠背部皮下分别植入甲基丙烯酰胺基明胶-软骨细胞复合体(对照组)、左旋聚乳酸多孔微球-甲基丙烯酰胺基明胶-软骨细胞复合体(多孔微球组)、接枝基质细胞衍生因子1左旋聚乳酸多孔微球-甲基丙烯酰胺基明胶-软骨细胞复合体(多孔微球修饰组),8周后取材,分别进行组织学染色与成软骨相关基因qRT-PCR检测。结果与结论:(1)相较于0,1 000 ng/mL基质细胞衍生因子1,500 ng/mL基质细胞衍生因子1可促进软骨细胞的增殖与迁移,提升软骨细胞内Ⅱ型胶原、弹性蛋白、增殖细胞核抗原、Bcl-2 mRNA表达;(2)基质细胞衍生因子1成功接枝于左旋聚乳酸多孔微球上,接枝率为93.75%;(3)相较于左旋聚乳酸多孔微球,接枝基质细胞衍生因子1左旋聚乳酸多孔微球可促进软骨细胞的增殖、黏附;(4)裸鼠皮下植入8周后,相较于对照组、多孔微球组,多孔微球修饰组具有更明显的软骨陷窝结构、更丰富的软骨特异性基质和Ⅱ型胶原沉积,弹性蛋白、Ⅱ型胶原、增殖细胞核抗原、Bcl-2 mRNA表达升高。结果表明:接枝基质细胞衍生因子1左旋聚乳酸多孔微球有利于软骨细胞的黏附、增殖、表型维持以及体内软骨组织形成。

BACKGROUND:The proliferation and phenotypic maintenance of chondrocytes are limited under two-dimensional culture conditions.Porous microspheres serve as scaffolds,providing a three-dimensional culture environment that better mimics in vivo growth conditions.Stromal cell derived factor-1,a homeostatic cytokine with potent chemotactic effects,facilitates cell adhesion and proliferation.OBJECTIVE:To investigate the impact of stromal cell derived factor-1 grafted poly-L-lactic acid porous microspheres on the biological characteristics of chondrocytes and the formation of cartilage tissue.METHODS:(1)The effects of different concentrations of stromal cell derived factor-1 on rabbit chondrocyte proliferation,migration,and phenotypic maintenance were investigated in an in vitro setting.(2)Poly-L-lactic acid porous microspheres were prepared by double emulsion method.Stromal cell derived factor-1 was grafted onto poly-L-lactic acid porous microspheres through carbodiimide reaction.The grafting was verified by enzyme-linked immunosorbent assay and incubation with stromal cell derived factor-1-specific fluorescent antibodies.(3)Rabbit chondrocytes were inoculated on poly-L-lactic acid porous microspheres and grafted on stromal cell derived factor-1 poly-L-lactic acid porous microspheres to detect cell proliferation and adhesion.(4)The methylacrylamide-gelatin-chondrocyte complex(control group),poly-L-lactic acid porous microsphere-methylacrylamide-gelatin-chondrocyte complex(porous microsphere group),and grafted stromal cell derived factor-1 poly-L-lactic acid porous microsphere-methylacrylamide-gelatin-chondrocyte complex(porous microsphere modified group)were implanted under the skin of the back of nude mice,respectively.Samples were collected 8 weeks later and detected using histological staining and qRT-PCR for chondroblast related genes.RESULTS AND CONCLUSION:(1)Compared with 0 and 1000 ng/mL stromal cell derived factor-1,1 and 500 ng/mL stromal cell derived factor 1 could promote the proliferation and migration of chondrocytes,and enhance the mRNA expression levels of type II collagen,elastin,proliferating cell nuclear antigen,and Bcl-2 in chondrocytes.(2)Stromal cell derived factor-1 was successfully grafted onto poly-L-lactic acid porous microspheres with a grafting rate of 93.75%.(3)Compared with poly-L-lactic acid porous microspheres,grafted stromal cell derived factor-1 poly-L-lactic acid porous microspheres promoted the proliferation and adhesion of chondrocytes.(4)After 8 weeks of subcutaneous implantation in nude mice,compared with the control group and the porous microsphere group,the porous microsphere modified group had clearer cartilage lacunae structure,more chondro-specific matrix and type II collagen deposition,and increased expression of elastin,type II collagen,proliferating cell nuclear antigen,and Bcl-2 mRNA.These findings indicate that stromal cell derived factor-1 grafted poly-L-lactic acid porous microspheres are beneficial to chondrocyte adhesion,proliferation,phenotypic maintenance,and the formation of cartilage tissue in vivo.