甲状腺素在骨髓间充质干细胞成软骨诱导过程中的作用

目的探讨甲状腺素在诱导骨髓间充质干细胞(BMSCs)软骨形成的作用。方法在两种条件培养基中培养和诱导猪BMSCs,对照组用成软骨培养基(含10-7 mol/L地塞米松和10 ng/mL TGFβ1),甲状腺素(T3)用成软骨培养基加100 nmol/L T3。MTT法检测BMSCs单层增殖情况。4周后取两组BMSCs Pellets,进行组织学染色和半定量基因表达分析。结果T3组BMSCs增殖明显高于对照组(P˂0.05)。T3组BMSCs Pellets形成典型软骨陷窝样结构,甲苯胺蓝染色阳性,并且优于对照组(P˂0.05)。与对照组相比,T3组第4周软骨生成标志基因Ⅱ型胶原(Col-Ⅱ)、聚集蛋白聚糖(aggrecan)和性别决定基因9(SOX9)的表达显著升高(P˂0.05),肥大标志基因Ⅹ型胶原(Col-Ⅹ),基质金属蛋白酶13(MMP13)基因的表达显著升高(P˂0.05),成骨基因Ⅰ型胶原(Col-Ⅰ),Runt相关转录因子2(RUNX2)表达在两组差异无统计学意义(P>0.05)。结论甲状腺素可促进间充质干细胞的增殖和软骨形成,同时诱导间充质干细胞分化的软骨细胞肥大,这些结果为研究软骨组织工程的诱导方案提供了有益的线索。

Role of thyroxine in chondrogenic induction of bone marrow mesenchymal stem cells

【Objective】To investigate the role of thyroxine in inducing chondrogenesis of bone marrow mesenchymal stem cells.【Methods】Porcine bone marrow stromal cells(BMSCs)were cultured and induced in two conditioned medium:Control group used chondrogenic medium(with 10^-7mol/L Dexamethasone and 10 ng/mL TGFβ1)and Thyroxine group(T 3 group)used chondrogenic medium plus 100 nmol/L T 3.BMSCs proliferation was evaluated by MTT assay in a monolayer way.BMSCs pellets in the two groups were harvested after 4 weeks and were evaluated with histological staining and semi-quantitative gene expression analysis.【Results】BMSCs proliferation in T 3 group was significantly higher than that of Control group(P?0.05).Better lacuna like structure and positive staining of toluidine blue were observed in BMSCs pellets in T 3 group.Expressions of marker genes of chondrogenesis,such as Col Ⅱ,aggrecan and SOX 9,were significantly increased in T 3 group compared with control at week 4,and expressions of Col X and MMP 13,marker genes of hypertrophy,were significantly increased in T 3 group(P?0.05).There was no significant difference in the gene expressions of ColⅠand RUNX 2 between the two groups(P>0.05).【Conclusion】Thyroxine promoted the proliferation and chondrogenesis of mesenchymal stem cells,and induced the hypertrophy and apoptosis of chondrocytes differentiated from mesenchymal stem cells.These results provide useful clues for the study of the pathogenesis of congenital chondrodysplasia.