辛伐他汀延缓生酮饮食导致的骨量丢失的实验观察

Simvastatin alleviates the bone loss caused by ketogenic diet: an in vivo study

目的分析辛伐他汀(ST)治疗后小鼠股骨骨微结构、力学性能及骨形态的改变,评价ST对缓解生酮饮食引起的骨量丢失的治疗作用。方法40只C57小鼠随机分为假手术组、卵巢切除组(OVX)、卵巢切除加辛伐他汀组(OVX+ST)、生酮饮食组(KD)及生酮饮食加辛伐他汀组(KD+ST),每组8只。OVX和OVX+ST组小鼠行双侧卵巢切除,予以常规标准饮食。KD及KD+ST组予以碳水化合物与脂肪比为1∶3的生酮饮食,OVX+ST及KD+ST组予以ST灌胃,剂量为20mg/(kg·d)。12周处死取材,测量各组小鼠血酮、血糖、血钙、血磷等的水平,分别采用显微CT扫描、三点弯曲试验、有限元分析及HE染色观察股骨骨量微结构、力学性能及骨形态。结果KD组和KD+ST组小鼠血酮含量为1.28mmol/L和1.48mmol/L,明显高于假手术组(0.60mmol/L)。各组间血糖、血钙或血磷的差异没有统计学意义。辛伐他汀治疗提高了KD+ST组的松质骨骨量、股骨有限元压缩刚度及三点弯曲刚度,其中KD+ST组较KD组股骨远端松质骨骨体积分数从4.1%上升到6.6%,有限元压缩刚度从35N/mm提高到161N/mm,股骨三点弯曲刚度从44N/mm提高到60N/mm,组织学观察也表明KD+ST组的股骨远端松质骨骨小梁较KD组明显增多。结论辛伐他汀治疗提高了KD组小鼠股骨松质骨骨体积分数、三点弯曲刚度、有限元压缩刚度和骨小梁数目,缓解了生酮饮食导致的骨量丢失。

Objective To observe the protective effect of simvastatin (ST) on osteoporosis caused by ketogenic diet by analyzing the alleviation of microstructure of the femur,mechanical properties,and bone morphology in mice treated with simvastatin. Methods A total of 40 C57 mice were randomly divided into Sham group,ovariectomized group (OVX),ovariectomized with simvastatin treatment group (OVX + ST),ketogenic diet group (KD),and the ketogenic diet with simvastatin treatment group (KD + ST) group,with 8 mice in each group. The mice in OVX and OVX+ST groups were undergone ovariectomy and fed with standard diet. The mice in KD and KD+ST groups were fed with ketogenic diet in which the ratio of carbohydrate and fat was 1 ∶3. The mice in the OVX + ST and KD + ST groups were administered with a dosage of 20 mg/(kg ·d) ST by gavage. Mice were sacrificed in 12 weeks. Serum ketone,glucose,calcium,and phosphorus were measured. The bone trabecular microstructure,biomechanical properties,and bone morphological changes were observed with micro CT scan,three-point bending tests,finite element analysis,and HE staining. Results The serum ketone level was significantly higher in the KD group (1.28 mmol/L) and the KD+ST group (1.48 mmol/L) than that in the Sham group (0.60 mmol/L). There were no significant differences in blood glucose,serum calcium,or phosphorus among these groups. Simvastatin treatment improved the cancellous bone number and the femoral compression stiffness in finite element analysis and the stiffness of three-point bending test in the KD+ST group. Compared with the KD group,the bone volume/tissue volume (BT/TV) in KD + ST group increased from 4.1% to 6.6%,the compression stiffness of finite element analysis increased from 35 N/mm to 161 N/mm,and the stiffness of three-point bending test increased from 44 N/mm to 60 N/mm. Histology analysis also showed that the distal femoral trabeculae in KD+ST group increased significantly than that in KD group. Conclusion Simvastatin alleviates bone loss in terms of the volume fraction of femoral cancellous bone,stiffness in three-point bending test,compression stiffness in finite element analysis,and trabeculae number in mice treated with ketogenic diet.