Hypoxia-Induced Autophagy Promotes Fracture Healing in Type 2 Diabetes Mellitus Rats

目的：研究低氧状态下自噬对2型糖尿病(Diabetes mellitus type 2, T2DM)合并股骨骨折大鼠模型不同时间点的骨折愈合程度及低氧诱导因子-1α (HIF-1α)、碱性磷酸酶(alkaline phosphatase, ALP)、Runt-相关转录因子-2 (Runx2)、微管相关蛋白1A/1B-轻链3 (LC3II/I)表达情况。方法：大鼠随机分为高糖高脂饲养前(Control)组、高糖高脂饲养8周后(HFD)组及T2DM模型(T2DM)组，采用高糖髙脂饲料联合链脲佐菌素制备T2DM模型，在T2DM模型基础上制作股骨骨折模型。实验大鼠分为对照组(T2DM合并股骨骨折模型组，Model)及治疗组(氯化钴(CoCl2)治疗的T2DM合并股骨骨折模型组，Treatment)，根据检测时间点每组继续分为造模后7 d、28 d、42 d的三个亚组。X线评估股骨愈合情况，WB检测HIF-1α、ALP、Runx2、LC3II/I表达。结果：T2DM合并股骨骨折模型随时间的增长，治疗组在第28 d相比于对照组已有较好的恢复，骨组织中ALP、Runx2表达增加，自噬蛋白LC3II/I的检测结果显示随时间增长自噬水平有所减弱。结论：低氧可以诱导自噬来促进T2DM大鼠骨折愈合。Objective: To investigate fracture healing and hypoxia-inducible factor-1α (HIF-1α), alkaline phosphatase (ALP), runt-related transcription factor 2 (Runx2), and microtubule associated protein-II/I (LC3II/I) expression at different time points in T2DM rats with femoral fracture under hypoxic conditions. Methods: The rats were randomly divided into high-sugar and high-fat pre-feeding groups, high-sugar and high-fat feeding groups after 8 weeks of feeding and a T2DM model group, T2DM was prepared with high-glucose and high-fat diet combined with streptavidin. Femoral fractures were modeled on the basis of T2DM. Experimental rats were divided into a control group (T2DM with femoral fracture model group, Model) and a treatment group (CoCl2 treatment group, Treatment) and continued to be divided into three subgroups on days 7, 28, and 42 post-molecularization for each group at the time of measurement. Femoral healing was assessed by X-ray. HIF-1α, ALP, Runx2, and LC3II/I expression was measured by Western blotting. Result: In the T2DM combined femoral fracture model, as time progresses, the treatment group shows better recovery compared to the control group at day 28. The expression of ALP and Runx2 in bone tissue increases, and the detection results of autophagy protein LC3II/I indicate that autophagy levels weaken over time. Conclusion: Hypoxia can induce autophagy to promote fracture healing in T2DM rats.