目的观察大鼠骨髓基质干细胞(BMSCs)在与大鼠生长板软骨细胞体外共培养条件下,BMSCs碱性磷酸酶(ALP)活性变化及成骨分化的标志骨钙素与Ⅰ型胶原mRNA水平表达的影响,从而认识生长板软骨细胞旁分泌作用对BMSCs分化的影响,以期帮助认识生长板损伤后骨桥形成的发生机制。方法大鼠BMSCs在与生长板软骨细胞进行间接共培养,并设阴性对照。测定ALP活性,用RT-PCR方法,检测Ⅰ型胶原与骨钙素mRNA的表达。结果BMSCs随共培养时间的延长,ALP活性明显升高,Ⅰ型胶原mRNA表达丰度明显高于对照组,骨钙素mRNA在对照组中几乎未见PCR扩增产物,共培养组在终末期则有一定的表达。结论BMSCs在与大鼠生长板软骨细胞体外共培养后,出现成骨分化倾向:随时间延长效应愈加显著,提示生长板软骨细胞的旁分泌作用可以促进BMSCs向成骨分化。 Objective To observe the changes of alkaline phosphatase (ALP) activity and the expression of osteocalcin (osteocalcin) and type Ⅰ collagen mRNA of rat bone marrow stromal stem cells (BMSCs) co-cultured with rat growth plate chondrocytes in vitro In order to understand the effect of growth plate chondrocyte paracrine on the differentiation of BMSCs in order to help understand the mechanism of bone formation after the growth plate injury. Methods BMSCs were co-cultured with growth plate chondrocytes and negative control was established. ALP activity was measured. The mRNA expression of type I collagen and osteocalcin mRNA was detected by RT-PCR. RESULTS: With the extension of co-culture time, ALP activity was significantly increased and the expression of type Ⅰ collagen mRNA was significantly higher than that of control group. There was almost no PCR amplification product of osteocalcin mRNA in control group. There is a certain expression. CONCLUSION: BMSCs tend to differentiate into osteoblasts after co-cultured with rat chondrocytes in vitro. The osteoblast differentiation tendency of BMSCs is more obvious with time prolonging, suggesting that the paracrine effect of chondrocytes on growth plate can promote the osteogenic differentiation of BMSCs.