中文摘要：

目的研究地塞米松（Dex）对大鼠肱骨形态结构的影响。方法 3月龄♀SD大鼠37只,随机分为基础组（B组）、正常对照组（C组,肌肉注射生理盐水）和实验组[低、中、高频率组（L、M、H组）分别2次/周、4次/周、6次/周肌肉注射Dex,每次1.0 mg.kg-1],给药30 d后取肱骨脱钙、石蜡包埋,骨形态计量学分析骨量、骨结构变化情况。结果肱骨上段松质骨：B、C组差异无显著性;与C组比较,L组差异无显著性,M、H组骨小梁面积百分数（Tb.Ar%）明显降低（P〈0.01）,骨小梁宽度、数目明显减少（P〈0.05）,分离度明显增加（M组P〈0.05;H组P〈0.01）。肱骨中段皮质骨：B、C组差异无显著性;与C组比较,L、M组变化差异无显著性,H组骨组织总面积、皮质骨面积百分数、皮质骨厚度均明显减少（P〈0.05）,骨髓腔面积百分数明显增大（P〈0.05）。肱骨生长板：B、C组差异无显著性;与C组比较,L、M和H组的生长板厚度均明显减少（P〈0.05）;L组肥大细胞直径变化无统计学意义,M、H组的肥大细胞直径明显减少（M组P〈0.01;H组P〈0.05）。结论短期、低频率（30d,每次1.0 mg.kg-1,2次/周）应用Dex不改变肱骨形态,当注射频率上升（4次/周）时仅观察到松质骨丢失,而皮质骨无变化,高频率时松质骨、皮质骨均严重丢失,3种频率用药均抑制肱骨生长板的生长发育,提示建立大鼠骨质疏松模型时应充分考虑不同用药频率对不同部位骨骼的影响,合理设计给药方案。

英文摘要：

Aim To determine the effects of dexamethasone（Dex） by histomorphometry on rat humerus.Methods Thirty-seven cases of female SD rats were randomly divided into basal control group（B group）,normal control group（C group was given physiological saline by intramuscular） and experimental groups [L,M and H group were given Dex（1.0 mg·kg-1） twice,four times and six times a week by intramuscular respectively for 30 days].The humerus was taken for bone histomorphometry after decalcification and paraffin-embedded.Results In PHM,there was no statistical significance between B and C group,or between L and C group.The trabecular bone area ratio（BV/TV）,trabecular thickness and trabecular quantity were significantly decreased in M and H group,while the trabecular separation degree was increased,compared with those in C group（P0.01,P0.05）.In HX,there was no statistical significance between B and C group,and no significant difference was found between C group and L or M group.Dex in H group was found to significantly reduce cortical bone and enlarge bone marrow cavity area compared with C group（P0.05）.In growth-plate,there was no statistical significance between B and C group.The thickness of growth-plate was reduced in all of the experimental groups,and the diameter of the mast cells was depressed in M（P0.01） and H（P0.05） group,compared with C group（P0.05）.Conclusions Short term,low frequency of Dex does not affect the humerus histomorphometry.The loss of trabecular bone precedes cortical bone loss with Dex use frequency increase.Moreover,the growth and development of growth-plate were inhibited by Dex.Our results suggest that different effects on different parts of the skeleton should be considered in GIOP model building.