Ajiro Yasumitsu, Tokuhashi Yasuaki, Matsuzaki Hiromi, Nakajima Shinya, Ogawa Takeshi
Department of Orthopedic Surgery, Nihon University School of Medicine, Tokyo, Japan.
Orthopedics. 2010 Feb;33(2):90-5. doi: 10.3928/01477447-20100104-14.
Many epidemiological surveys have identified smoking as a risk factor for osteoporosis, but it is unclear whether smoking has a direct effect on bone metabolism and if such an effect could cause osteoporosis. Therefore, we examined whether smoking causes osteoporosis based on the impact of smoke exposure on the bones of rats. A rat model of passive cigarette smoking was prepared by breeding rats in a cigarette-smoking box for 4 or 8 weeks. Histological changes, micro-computed tomographic (CT) analysis, mechanical bone strength, and bone mineral density of the femur and lumbar vertebrae were examined in these rats and in control rats that were not exposed to smoke. Lower mechanical bone strength was observed in smoke-exposed rats, but these differences were not significant. Significantly lower bone mineral density was found in the femur (P<.01) and lumbar bones (P<.001) of 8-week smoke-exposed rats compared to controls. In a micro-CT scan of lumbar vertebrae, the bone volume, trabecular thickness, trabecular number, and trabecular separation differed significantly between smoke-exposed rats and controls. Histologically, the osteocytes in the smoke-exposed rats were small (approximately 25% of the size in controls), and decreased numbers of marrow cells and osteoblasts (P<.01), as well as a black carbon dust-like substance, were found in the bone of smoke-exposed rats. These results indicate that smoking significantly decreases bone mineral density, which causes osteoporosis, and the organizational changes in the bone suggest a direct effect of smoking on bone structure. Fewer marrow cells were present in the smoke-exposed rats, and a black carbon dust-like substance was observed.
许多流行病学调查已将吸烟确定为骨质疏松症的一个风险因素，但尚不清楚吸烟是否对骨代谢有直接影响，以及这种影响是否会导致骨质疏松症。因此，我们基于烟雾暴露对大鼠骨骼的影响，研究了吸烟是否会导致骨质疏松症。通过将大鼠饲养在吸烟箱中4周或8周，制备了被动吸烟的大鼠模型。对这些大鼠以及未暴露于烟雾的对照大鼠的股骨和腰椎进行了组织学变化、显微计算机断层扫描（CT）分析、骨机械强度和骨矿物质密度检查。在暴露于烟雾的大鼠中观察到较低的骨机械强度，但这些差异不显著。与对照组相比，暴露于烟雾8周的大鼠股骨（P<0.01）和腰椎（P<0.001）的骨矿物质密度显著降低。在腰椎的显微CT扫描中，暴露于烟雾的大鼠和对照组之间的骨体积、小梁厚度、小梁数量和小梁间距存在显著差异。组织学上，暴露于烟雾的大鼠中的骨细胞较小（约为对照组大小的25%），并且在暴露于烟雾的大鼠的骨骼中发现骨髓细胞和成骨细胞数量减少（P<0.01），以及一种类似黑炭粉尘的物质。这些结果表明，吸烟会显著降低骨矿物质密度，从而导致骨质疏松症，并且骨骼中的组织变化表明吸烟对骨骼结构有直接影响。暴露于烟雾的大鼠中骨髓细胞较少，并且观察到一种类似黑炭粉尘的物质。
