目的探讨短期使用糖皮质激素对大鼠不同部位骨骼的形态结构和生物力学的影响。方法20只3月龄SD雌性大鼠随机分为2组:①正常对照组(Ctrl);②糖皮质激素组(dexamethasone,Dex)。每只大鼠适应性喂养1周后,灌胃6周,取左侧胫骨上段(proximal tibia metaphyses,PTM)和中段(middle part of tibia shaft,TX)进行骨形态计量学检测,取左侧股骨(Left Femur,LF)和第5腰椎(the5th Lumbar Vertebra,LV5)进行骨生物力学检测。结果Ctrl组大鼠的体重随时间(6周)逐渐增加;而Dex组大鼠的体重增加缓慢,甚至出现体重下降的情况,两组大鼠的体重差异具有显著性。与Ctrl组比,Dex组大鼠软组织中:肝、脾、肾、子宫和胸腺重量显著性减少。骨形态计量学静态参数显示:与Ctrl组相比,Dex组大鼠TX段皮质骨的骨量明显降低,骨髓腔增大。动态参数显示:Dex组大鼠的骨内膜面荧光周长百分率、骨形成率明显降低,而骨吸收百分率增加;骨外膜面动态参数无显著性变化,两组大鼠PTM松质骨无论静态参数或动态参数与对照组比无统计学上的显著性变化。Dex也没有弱化LF和LV5的力学性能(最大载荷,最大应力,最大应变)。结论短期、少量使用Dex(45d,2.5mg·kg-1,twice per week),仅使大鼠皮质骨丢失,由于几何形状的变化,并不改变生物力学的性能。以这种方式使用Dex,不仅不影响松质骨,也不改变大鼠的生物力学性能。此结论提示Dex短期使用对不同部位的骨骼影响不同,先出现皮质骨的变化。因此需要重视对糖皮质激素导致皮质骨变化的观察和研究。 Objective To investigate the effect of short-term glucocorticoid on the morphological structure and biomechanics of different parts of the skeleton in rats. Methods Twenty female SD rats of 3 months old were randomly divided into 2 groups: ① normal control group (Ctrl); ② dexamethasone (Dex) group. One week after adaptive feeding, each rat was gavaged for 6 weeks. Bone morphometry was performed on the left proximal tibia metaphyses (PTM) and middle part of tibia shaft (TX). Left femur (Left Femur, LF) and the 5th Lumbar Vertebra (LV5) for biomechanical testing. Results The body weight of rats in Ctrl group increased gradually with time (6 weeks). However, the body weight of Dex rats increased slowly and even decreased. The body weight of rats in both groups were significantly different. Compared with the Ctrl group, Dex group rats soft tissue: liver, spleen, kidney, uterus and thymus weight decreased significantly. The static parameters of bone morphometry showed that compared with the Ctrl group, the bone mass of the TX segment of Dex group was significantly decreased and the marrow cavity was increased. The dynamic parameters showed that the percentages of peri-luminal fluorescence, the rate of bone formation, and the percentage of bone resorption in Dex group rats were significantly increased, while the dynamic parameters of the periosteal surface had no significant changes. The PTM cancellous bone in both groups had no significant difference There was no statistically significant difference between the static parameters or the dynamic parameters and the control group. Dex also did not weaken the mechanical properties of LF and LV5 (maximum load, maximum stress, maximum strain). Conclusions Short-term and small-scale use of Dex (45d, 2.5mg · kg-1, twice per week) only resulted in the loss of cortical bone in rats, which did not change the biomechanical properties due to the changes in geometry. Using Dex in this manner not only did not affect cancellous bone, nor did it alter the biomechanical properties of the rat. This conclusion suggests that Dex short-term use of bone in different parts of different effects, the first cortical bone changes. Therefore, we need to pay attention to the glucocorticoid-induced cortical bone changes observed and studied.