MicroPET/CT评价去卵巢大鼠骨代谢变化的实验研究

目的探讨使用microPET/CT扫描仪对骨质疏松非创伤性探查的可行性,分析去卵巢大鼠雌激素缺乏引起骨质疏松的骨代谢变化。方法 12只6月龄雌性未孕Sprague-Dawley大鼠,体重290 g～310 g,随机分为两组(n=6):去卵巢组(OVX)和假手术组(SHAM)。用microPET/CT扫描仪进行骨显像,检测大鼠第4腰椎椎体、左股骨近端,左股骨干以及左胫骨中段对核素显像剂18F-F-的摄取。骨显像检测后腹主动脉放血法处死大鼠,取子宫称重,收集第4腰椎、左侧股骨和胫骨,用双能X线骨密度检测仪(DXA)测定第4腰椎椎体、左股骨近端,左股骨干以及左胫骨干的骨密度,取大鼠右侧胫骨制备成不脱钙硬组织切片进行形态学观察。结果 OVX组第4腰椎椎体、左股骨近端,左股骨干以及左胫骨干的骨密度比SHAM组有显著性下降。与SHAM组比较,microPET/CT骨显像可见OVX组第4腰椎椎体、左股骨近端,左股骨干以及左胫骨干核素浓聚,去卵巢大鼠骨骼兴趣区PET影像强度增加。两组大鼠胫骨干的骨几何结构参数比较无显著性差异,OVX组大鼠胫骨近端松质骨的结构参数与SHAM组比较有明显变化。OVX组大鼠胫骨近端的骨形成参数矿化表面、矿物质沉积率和骨形成率比SHAM组有显著性升高。两组大鼠胫骨第4腰椎椎体、左股骨近端,左股骨干以及左胫骨干PET影像强度与其骨密度之间呈显著性负相关。结论 MicroPET/CT可用于骨质疏松大鼠的骨代谢研究,为临床诊断骨质疏松新方法研究提供了新思路。

MicroPET/CT assessment of the changes of bone metabolism in ovariectomized rats

Objective To explore the feasibility of non-invasive detection of bone metabolism in vivo by utilizing the microPET/CT scanner, and to analyze the changes of bone metabolism in overiectomized rats.Methods Twelve 6-month non-pregnant female SD rats, weighting 290-310g, were randomly divided into two groups: ovariectomy ( OVX) group and sham-operation ( SHAM) group.Bone imaging of all the rats were performed using a dedicated small animal PET scan with 18 F-fluoride.The fluoride uptake value and BMD were quantified at the 4th lunbar vertebra, the left proximal femur, the femoral disphysis, the tibial midshafts, and the right tibia.After imaging, all the rats bled to dead through the abdominal aorta.The uterus was collected and weighed.The 4th lumar vertebra, the left proximal femur, the left femoral disphysis, and the tibial midshafts were collected and BMD of these parts was detected using DXA.The right tibia was obtained for the histomorphometric measurement.Results BMD of L4, the left proximal femur, the femoral disphysis, and the tibial midshafts in OVX group was significantly lower than that in SHAM group.Compared with that in SHAM group, the image intensity of L4, the left proximal femur, the femoral disphysis, and the tibial midshafts in microPET/CT in OVX group was significantly higher than that in SHAM group (P<0.05).And the intensity of bone ROI in OVX rats increased.No significant difference of the bone histomorphometric variables of the femoral disphysis between the two groups was observed.But the histomorphometric variables of the cancellous bone of the proximal femur were significantly different between the two groups.The PET image intensity of the left proximal femur, the femoral disphysis, and the tibial midshafts was negatively correlated with BMD.Conclusion MicroPET/CT is a useful non-invasive method to detect and quantify bone metabolism, which can provide a new method to diagnose osteoporosis.