Kitasato University School of Medicine, Department of Orthopaedic Surgery, 1–15–1 Kitasato, Sagamihara, Kanagawa 228-8555, Japan .
Exp Anim. 2011;60(5):455-62. doi: 10.1538/expanim.60.455.
To clarify the distribution of bone-marrow-derived cells in fractures treated by plate fixation, fracture models were created using the green fluorescent protein (GFP) chimeric mouse. We observed 2 types of fracture healing processes with different types of callus formation and cellular events by using Mouse Fix™, a device allowing plate fixation on the mouse femur, and differences in the distribution of bone-marrow-derived cells between the 2 types. The GFP chimeric mice were created by bone marrow transplantation. Fractures were created on the left femurs of mice and stabilized with either rigid (Group R) or flexible (Group F) plates to prepare undecalcified fresh-frozen sections. In Group F, a large external callus and a large intramedullary callus were formed mostly by endochondral ossification. The cells that made up the intramedullary callus and callus in the fracture gap were GFP positive, but most cells of the external callus were not. In Group R, bone union was achieved mostly without external callus formation, bone apposition occurred directly in the gap, and a small intramedullary callus was formed. As observed in Group F, this group had GFP-positive cells in the callus within the fracture gap and in the intramedullary calluses. The results of this study provided direct evidence of the distribution of bone-marrow-derived cells in the callus of fractures treated by plate fixation under different stability conditions.
为了阐明通过钢板固定治疗骨折时骨髓源性细胞的分布，我们使用绿色荧光蛋白（GFP）嵌合小鼠创建了骨折模型。我们使用 Mouse Fix™（一种允许在小鼠股骨上固定钢板的设备）观察了两种不同类型的骨折愈合过程，这两种过程具有不同类型的骨痂形成和细胞事件，并观察了两种过程中骨髓源性细胞分布的差异。GFP 嵌合小鼠是通过骨髓移植创建的。在小鼠的左股骨上创建骨折，并使用刚性（R 组）或柔性（F 组）钢板稳定骨折，以制备未脱钙新鲜冷冻切片。在 F 组中，大量的外部骨痂和大量的髓内骨痂主要通过软骨内骨化形成。构成髓内骨痂和骨折间隙内骨痂的细胞是 GFP 阳性的，但外部骨痂的大多数细胞不是。在 R 组中，主要通过无外部骨痂形成实现骨愈合，骨直接在间隙中附着，并且形成小的髓内骨痂。与 F 组一样，在该组中，在骨折间隙内的骨痂和髓内骨痂中观察到 GFP 阳性细胞。这项研究的结果提供了直接证据，证明了在不同稳定性条件下通过钢板固定治疗骨折时，骨髓源性细胞在骨痂中的分布。
