DDR2基因缺失对小鼠骨髓间充质干细胞生物学特性的影响

Biological Characteristics of Bone Marrow Mesenchymal Stem Cells(BMSCs) Derived from Discoidin Domain Receptor 2 Knockout Mice

目的:骨髓间充质干细胞(Bone Mesenchymal Stem Cells,BMSCs)是骨再生工程中重要的种子细胞,它对骨组织缺损的修复有着良好的效果。但是BMSCs向成骨细胞分化并修复骨组织缺损是是由细胞外因子共同作用产生的结果。DDR2(Discoidin Domain Receptor 2)作为I型胶原的特异性受体在成骨细胞的分化中发挥重要的调节作用。而对于其在BMSCs向成骨细胞的分化过程中的所起到的作用还鲜有研究,对其作用机理尚不明确。因此我们希望通过分离、培养并鉴定比较DDR2基因缺失小鼠与野生型小鼠来源的骨髓间充质干细胞了解其生物学特性,为后续的实验奠定理论基础。方法:采用改良型的全骨髓贴壁细胞分离方法分离培养两种小鼠来源的骨髓间充质干细胞,采用流式细胞技术鉴定其表面标记物的表达,并利用诱导培养液诱导骨髓间充质干细胞向成骨细胞和成脂肪细胞分化。结果:分离培养的两种骨髓间充质干细胞形态一致,增殖能力和自我更新能力强,流式细胞术检测其表面标记物CD29,Sca-1均表达阳性,CD105,CD45表达为阴性,分离得到的两种细胞均有向成骨细胞和成脂肪细胞分化的能力,但可以明显观察到DDR2基因缺失小鼠的骨髓间充质干细胞的成骨分化能力减弱。结论:本实验通过对于DDR2基因缺失小鼠BMSCs分离、培养和鉴定,初步探索DDR2基因缺失在在成骨过程中的作用结果,为进一步研究提高BMSCs的成骨分化能力奠定理论基础。经实验证明,DDR2基因缺失小鼠来源的骨髓间充质干细胞虽然仍具备干细胞的生物学特性,但其向成骨细胞的分化能力明显减弱,说明DDR2基因缺失对其骨髓间充质干细胞的成骨分化等有着重要的影响。

Objective： Bone Mesenchymal Stem Cells are a kind of stem cell, which are the common cell source of osteoblasts, have good ability to repair bone defects. However, the differentiation of BMSCs into osteoblasts is a very complicated process, DDR2 （Discoidin Domain Receptor 2） as a specific receptors of type I collagen, plays an important role in regulation ofosteoblast differentiation. However, the function of DDR2 on the osteogenic differentiation of BMSCs is rarely studied, and its functional mechanism is also unclear. Therefore, we hope that through isolated, cultured and identified comparison between DDR2 gene deletion in mice and wild-type mice bone marrow-derived mesenchymal stem cells to understand their biological characteristics, the theoretical basis for the subsequent experiments. Methods： BMSCs were isolated from DDR2 knockout mice by using a modified adherent culture method, and general BMSCs surface markers were detected by flow cytometry method. To detect their differentiation capacity, BMSCs were differentiated into osteoblasts and adipocytes. Upon certain induction conditions. Results： The BMSCs showed spindle-shape morphology and high capacity of proliferation and self-renewal. The cells were CD105^＋ and Sca-1^＋, but CD29^- and CD45-. They also showed the differentiation capacity into osteoblasts and adipocytes. Conclusions： In this study, we isolated, cultured and identified the BMSCs derived from DDR2 gene knockout mice and explored the influence of DDR2 on the biological characteristics and osteogenic ability of BMSCs,to lay the theoretical foundation for the promotion of BMSCs ability on bone regeneration. These results illustrated that BMSCs derived from DDR2 knockout mice have perfect stem biological characteristics, but their differentiation ability into osteoblasts are significantly reduced, which suggests that DDR2 has very important role in BMSCs＇ differentiation.