Department of Orthopaedic Surgery and Rehabilitation, Loyola University Stritch School of Medicine, Maywood, IL, USA.
J Orthop Trauma. 2012 Dec;26(12):712-8. doi: 10.1097/BOT.0b013e3182724298.
Clinical studies have shown alcohol to be a risk factor for traumatic orthopaedic injuries and for nonunion. Data from animal studies suggest that alcohol exposure inhibits fracture healing. This report presents a novel rodent model of impaired fracture healing caused by repeated alcohol exposure. Using this model, we examined the regenerative effects of an intravenously administered population of isolated and expanded mesenchymal stem cells (MSCs) on fracture healing.
Bone marrow-derived MSC were isolated from transgenic green fluorescent protein C57BL/6 mice, and culture expanded using a lineage depletion protocol. Adult wild-type C57BL/6 mice were subjected to a 2-week binge alcohol exposure paradigm (3 days during which they received daily intraperitoneal injections of a 20% alcohol/saline solution followed by a 4-day rest period and another binge cycle for 3 consecutive days). At completion of the second binge cycle, mice were subjected to a mid-shaft tibia fracture while intoxicated. Twenty-four hours after the fracture, animals were administered an intravenous transplant of green fluorescent protein-labeled MSC. Two weeks after the fracture, animals were euthanized and injured tibiae were collected and subjected to biomechanical, histologic, and microcomputed tomography analysis.
Pre-injury binge alcohol exposure resulted in a significant impairment in biomechanical strength and decrease in callus volume. MSC transplants restored both fracture callus volume (P < 0.05) and biomechanical strength (P < 0.05) in animals with alcohol-impaired healing. In vivo imaging demonstrated a time-dependent MSC migration to the fracture site.
These data suggest that a 2-week binge alcohol exposure significantly impairs fracture healing in a murine tibia fracture model. Intravenously administered MSC were capable of specifically homing to the fracture site and of normalizing biomechanical, histologic, and microcomputed tomography parameters of healing in animals exposed to alcohol. Understanding MSC recruitment patterns and functional contributions to fracture repair may lead to their use in patients with impaired fracture healing and nonunion.
临床研究表明，酒精是创伤性骨科损伤和骨折不愈合的危险因素。动物研究的数据表明，酒精暴露会抑制骨折愈合。本报告介绍了一种新的酒精反复暴露导致骨折愈合受损的啮齿动物模型。使用该模型，我们研究了静脉内给予分离和扩增的间充质干细胞（MSCs）群体对骨折愈合的再生作用。
从转基因绿色荧光蛋白 C57BL/6 小鼠的骨髓中分离 MSC，并使用谱系耗竭方案进行培养扩增。成年野生型 C57BL/6 小鼠接受为期 2 周的 binge 酒精暴露方案（3 天，每天接受腹腔内注射 20%酒精/盐水溶液，然后休息 4 天，再进行连续 3 天的 binge 周期）。在第二个 binge 周期结束时，小鼠在醉酒时接受了中段胫骨骨折。骨折后 24 小时，动物接受静脉注射绿色荧光蛋白标记的 MSC。骨折后 2 周，处死动物并采集受伤胫骨，进行生物力学、组织学和微计算机断层扫描分析。
预先的 binge 酒精暴露导致生物力学强度显著降低和骨痂体积减少。MSC 移植恢复了酒精损害愈合的动物的骨折骨痂体积（P < 0.05）和生物力学强度（P < 0.05）。体内成像显示 MSC 随时间向骨折部位迁移。
这些数据表明，2 周 binge 酒精暴露显著损害了小鼠胫骨骨折模型中的骨折愈合。静脉内给予的 MSC 能够特异性归巢到骨折部位，并使暴露于酒精的动物的生物力学、组织学和微计算机断层扫描愈合参数正常化。了解 MSC 募集模式和对骨折修复的功能贡献可能导致它们在骨折愈合受损和骨不连的患者中的应用。
