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观察不同剂量地塞米松(Dex)对大鼠骨质量的影响并探讨其作用机制。31只3月龄SPF级雌性SD大鼠随机分为4组:对照组(saline 7只)、Dex-L组(1 mg/kg 8只)、Dex-M组(2.5 mg/kg 8只)、Dex-H组(5 mg/kg 8只);尾静脉注射Dex,2次/周,8周后处死。取胫骨上段制作不脱钙骨切片进行骨形态计量学分析,取左侧尺骨用于测定钙、磷和羟脯氨酸含量,股骨进行骨密度(BMD)和生物力学检测。结果表明:与对照组相比,Dex各组体重均显著下降;胫骨荧光周长百分率、矿化沉积率、骨形成率等显著降低,骨小梁面积百分数,骨小梁数目显著增加,骨小梁分离度显著减少;Dex-L BMD和Dex-M羟脯氨酸含量明显下降,Dex各组力学参数显著降低。提示:Dex显著抑制骨形成,降低骨转换,随着剂量增加,骨小梁面积百分数增加,BMD和骨生物力学性能下降,同时骨内有机质合成降低,非矿化骨形成增加,骨质量降低。以1 mg/kg的Dex对骨的质量影响最明显,该剂量略增加骨小梁面积百分数,但骨形成、骨生物力学性能、骨内有机质含量明显下降。不同剂量的Dex对骨质量的影响不同,剂量与骨质量之间无比例依赖关系。
To observe the effects of different doses of dexamethasone (Dex) on the bone quality of rats and to explore its mechanism. Thirty-one three-month-old SPF female Sprague-Dawley rats were randomly divided into four groups: control group (7 rats in saline group), Dex-L group (8 mg / kg), Dex-M group (2.5 mg / , Dex-H group (5 mg / kg 8); tail vein injection Dex, 2 times / week, 8 weeks after sacrifice. The upper part of the tibia was used to make non-decalcified bone slices for bone histomorphometry. The left ulna was used to determine calcium, phosphorus and hydroxyproline contents, and femur BMD and biomechanical measurements. The results showed that compared with the control group, the body weight of Dex groups decreased significantly. The percentages of perimeter of tibia, the rate of mineralized deposition and the rate of bone formation were significantly decreased. The percentage of trabecular area and trabecular number were significantly increased. Beam separation significantly reduced; Dex-L BMD and Dex-M hydroxyproline content decreased significantly Dex mechanical parameters were significantly reduced. It is concluded that Dex significantly inhibits bone formation and decreases bone turnover. As the dose increases, the trabecular area increases, the biomechanical properties of BMD and bone decrease, the synthesis of organic matter decreases, the formation of non-mineralized bone increases, and the bone quality decreases. Dex at 1 mg / kg had the most obvious effect on the bone mass, but this dose slightly increased the trabecular area percentage, but the bone formation, bone biomechanical properties and the content of organic matter in the bone decreased significantly. Different doses of Dex have different effects on bone mass, and there is no proportional dependence between dose and bone mass.