沙格列汀和艾塞那肽对糖尿病性骨质疏松大鼠松质骨的影响

Effects of Saxagliptin and Exenatide on Humerus Cancellous Bone of Diabetes-induced Osteopenia Rats

目的研究沙格列汀和艾塞那肽对糖尿病性骨质疏松大鼠肱骨松质骨的影响。方法 35只雌性SD大鼠随机分为正常组、对照组和待建模组,待建模组大鼠采用高脂高糖饮食喂养联合低剂量链脲佐菌素(30 mg·kg^(-1))诱导2型糖尿病,以注射链脲佐菌素10 d后口服葡萄糖耐量试验2 h大于11.1 mmol·L^(-1)、最高血糖大于16.7 mmol·L^(-1)为成模标准,筛选出糖尿病模型大鼠并随机分为模型组、沙格列汀组和艾塞那肽组,给药30 d后处死大鼠,分取左侧肱骨上段,4%多聚甲醛固定48 h,脱水透明后,采用甲基丙烯酸甲酯塑料包埋技术制作标本,切片后经Masson-Goldner Trichrome染色,以骨组织形态计量学分析骨量、骨结构变化情况。结果松质骨形态学结果:正常组、对照组无显著差异,与对照组相比,模型组大鼠松质骨的骨量显著丢失(P<0.01),骨小梁数目明显降低(P<0.01),分离度明显增加(P<0.01);与模型组相比,沙格列汀组、艾塞那肽组大鼠松质骨的骨量显著增加(P<0.01),骨小梁数目明显升高(P<0.01),分离度明显减小(P<0.01)。松质骨细胞参数:正常组、对照组无显著差别,与对照组相比,模型组大鼠的成骨细胞数(P<0.05)及成骨细胞周长百分数(P<0.01)明显降低,破骨细胞数及破骨细胞周长百分数显著上升(P<0.01);与模型组相比,沙格列汀组、艾塞那肽组大鼠的成骨细胞数(P<0.01)及成骨细胞周长百分数(沙格列汀组P<0.05,艾塞那肽组P<0.01)均显著上升,而两组的破骨细胞数(P<0.01)、破骨细胞周长百分数(P<0.05)均显著下降。肱骨生长板:正常组、对照组无显著差别,与对照组相比,模型组大鼠的生长板厚度明显降低(P<0.01)、肥大细胞直径显著减少(P<0.01);与模型组相比,沙格列汀组、艾塞那肽组大鼠的生长板厚度(P<0.01)和肥大细胞直径(P<0.05)均明显增加。结论沙格列汀和艾塞那肽均呈现对大鼠糖尿病性骨质疏松的治疗作用,其机制可能与二者改善生长板的生长率、改变糖尿病造成的低骨转换状态有关。

OBJECTIVE To determine the effects of saxagliptin and exenatide on humerus cancellous bone of diabetes-induced osteopenia rats by histomorphometry.METHODS Thirty-five Cases of female SD rats were randomly divided into normal group（N group,n = 7）,control group（C group,n = 7）,and the remaining rats were used to establish the type 2 diabetic model by combination of high-fatsugar-diet feeding for 4 weeks and then low-dose streptozotocin injection（STZ,30 mg·kg^（-1））.After 10 d,the oral glucose tolerance test and the fasting blood glucose were measured,rats with high OGTT（2 h） above 11.1 mmol·L^（-1）and high FBG above 16.7 mmol·L^（-1）were divided into model group（M group,n = 5）,saxagliptin group（G group,n = 5） and exenatide group（D group,n = 6）,and continuously treated for 30 d.The left humerus（proximal humeru metaphometry,PHM） were fixed with 4%paraformaldehyde for 48 h,uncalcified embedded in methyl methacrylate after dehydrated and cleared,and sections were taken for bone histomorphometry after Masson-Goldner Trichrome stained.RESULTS In PHM,there was no statistical significance between N and C group,the trabecular bone area ratio（BV/TV） and trabecular quantity were significantly decreased（P〈0.01） in M group,while the trabecular separation degree was increased,comparing with those in C group（P〈0.01）,and the trabecular bone area ratio（BV/TV） and trabecular quantity in G and D group were higher（P〈0.01） than those of model rats,while the trabecular separationdegree was decreased,comparing with those in M group（P〈0.01）.Cell parameters showed no statistical significance between N and C group,the osteocllast number and percentage of osteocllast surface perimeter were significantly reduced（P〈0.05,P〈0.01） in M group,while the osteoclast number and percent osteocllast surface perimeter were significantly increased（P〈0.01） as compared with those in C group,saxagliptin and exenatide were found to significantly induce osteocllast number（P〈0.01） and percentage of osteoblast surface perimeter（G group P〈0.05,D group P〈0.01）,while reduce osteoclast number（P〈0.01） and percent osteoblast surface perimeter（P〈0.05） compared with M group.In growth-plate,there was no statistical significance between N and C group,the thickness of growth-plate and the diameter of the mast cells were reduced in M groups（P〈0.01）,while the thickness of growthplate（P〈0.01） and the diameter of the mast cells（P〈0.05） were increased in G and D group,compared with M group.CONCLUSION Therapeutic effects of saxagliptin and exenatide on diabetes-induced osteopenia rats was showed,and the mechanism may be related to the improved growth rate of growth-plate and the changed bone turnover status.