Milne M, Quail J M, Baran D T
Department of Orthopedics, University of Massachusetts Medical School, Worcester 01655, USA.
J Cell Biochem. 1998 Dec 1;71(3):382-91.
Osteoblast-like cell cultures have been established from the marrow of adult rat vertebrae. We have simultaneously examined the response to dexamethasone (dex) treatment in cultures of young adult female vertebral and femoral marrow cells. Alkaline phosphatase (AP) activity was analyzed as well as the expression of mRNAs for osteocalcin (OC) and insulin-like growth factor I (IGF-I). The vertebral and femoral marrow cells were maintained for 7 days in primary culture with or without 10(-8) M dex and then 6 days in secondary culture without dex or with 10(-8) M or 10(-7) M dex. All cells were examined on day 6 of secondary culture. Vertebral and femoral cultures each expressed the highest AP enzyme levels when grown with dex in primary culture (10(-8) M) and secondary culture (10(-7) M). Under all experimental conditions, vertebral cultures had lower AP enzyme activity than femoral cultures. When dex was omitted from secondary culture, OC gene expression was not detected in either vertebral or femoral passaged cells even if dex was present in primary culture. For dex conditions where OC was expressed, vertebral cultures had higher OC mRNA steady-state levels than femoral cultures. IGF-I gene expression was detected by Northern analysis in both vertebral and femoral secondary cultures. However, vertebral marrow cultures had much higher IGF-I mRNA levels compared to femoral cultures whether or not dex was present in primary culture. These findings demonstrate that dex supports the differentiation of both vertebral and femoral adult marrow osteogenic cells into osteoblasts. Our results support the hypothesis that osteoblastic marrow cultures differ depending upon which location in the skeleton they are from and that there are skeletal site-dependent differences in the insulin-like growth factor system components.
已从成年大鼠椎骨骨髓中建立了类成骨细胞培养物。我们同时检测了成年雌性大鼠年轻椎骨和股骨骨髓细胞培养物对地塞米松（dex）处理的反应。分析了碱性磷酸酶（AP）活性以及骨钙素（OC）和胰岛素样生长因子I（IGF-I）的mRNA表达。将椎骨和股骨骨髓细胞在含有或不含有10(-8) M地塞米松的原代培养中培养7天，然后在不含地塞米松或含有10(-8) M或10(-7) M地塞米松的传代培养中培养6天。在传代培养的第6天对所有细胞进行检测。在原代培养（10(-8) M）和传代培养（10(-7) M）中添加地塞米松培养时，椎骨和股骨培养物的AP酶水平均最高。在所有实验条件下，椎骨培养物的AP酶活性均低于股骨培养物。当传代培养中不添加地塞米松时，即使原代培养中存在地塞米松，在传代的椎骨或股骨细胞中也未检测到OC基因表达。对于表达OC的地塞米松条件，椎骨培养物的OC mRNA稳态水平高于股骨培养物。通过Northern分析在椎骨和股骨传代培养物中均检测到IGF-I基因表达。然而，无论原代培养中是否存在地塞米松，椎骨骨髓培养物中的IGF-I mRNA水平均远高于股骨培养物。这些发现表明，地塞米松支持成年椎骨和股骨骨髓成骨细胞向成骨细胞的分化。我们的结果支持以下假设：成骨骨髓培养物因来源于骨骼的不同位置而有所差异，并且胰岛素样生长因子系统成分存在骨骼部位依赖性差异。
