应用pQCT与DXA定量检测去卵巢大鼠股骨近端骨质疏松建模效果的对比研究

目的比较pQCT与DXA定量检测去卵巢大鼠股骨近端骨质疏松的建模效果的能力。方法16只8月龄Wistar雌性大鼠(平均体重350g)随机分为模型组(卵巢切除组)与对照组(卵巢假切除组)。术后3个月,取大鼠左侧股骨。应用肢体计算机断层扫描(pQCT)与双能X线骨密度仪(DXA)对骨质疏松建模效果进行对比研究:(1)确定pQCT与DXA测量精度,即计算重复测量的精度误差;(2)比较应用两种骨密度仪所测得的对照组、模型组的骨密度、骨矿含量、骨几何结构参数及其相关系数。结果(1)pQCT总骨及松质骨体密度的测量精度误差分别为2.27%与2.00%,而DXA骨面密度的测量精度误差为3.36%。(2)模型组pQCT总骨体密度和松质骨体密度分别低于对照组8.2%和15.0%犤(模型组-对照组)/对照组×100%犦,差异有显著性(P<0.01);而模型组DXA骨面密度低于对照组3.0%,差异无显著性(P>0.05)。模型组pQCT总骨骨矿含量低于对照组3.7%,差异无显著性(P>0.05),而松质骨骨矿含量低于对照组11.4%,差异有显著性(P<0.05);模型组DXA骨矿含量低于对照组3.0%,差异无显著性(P>0.05)。(3)DXA骨矿含量与pQCT总骨骨矿含量之间呈正相关(r=0.82,P<0.001);DXA骨投影面积与pQCT骨体积之间亦呈正相关(r=0.52,P<0.05);DXA骨面密度与pQCT总骨体密度之间无相关关系(r=0.14,P>0.05)。DXA

Comparison of pQCT and DXA analysis for establishment of osteoporotic model in proximal femur of mature ovariectomized rats

Objective To compare the capability of pQCT and DXA in evaluation of proximal femur osteoporosis model establishment i nduced by ovariectomy (Ovx)in mature rats.Methods Sixteen8-month-old breeder Wistar rats(mean body weight of 350g )were randomized into Ovx group and Sham-operated group.All rats were e uthanized 3months after surgery.The left femur of each rat was retrieved for the following evaluations at the proximal femur:1)To compare the reproducibility(precision error)of the repeated measurements of the proxim al femur between pQCT(volumetric densitometer)and DXA(areal den-sitometer);2)to compare the differences in measur ement results of the proximal femur between Ovx group and Sham-operated group,including bon e mineral content (BMC),bone mineral density(BMD),bone geometry,and their correlations.Results1)The precision error of pQCT total volumetric BMD and trabecular volu-metric BMD were 2.27%and 2.00%respectively,while that of DXA areal BMD w as 3.36%.2)The pQCT total and trabecular volumetric BMD in Ovx rats was 8.2%and 15.0%lower th an that in Sham-operated rats(P<0.01),while the areal BMD measured by DXA i n Ovx rats was only 3.0%lower than that in Sham-operated rats(P>0.05).The pQCT total BMC in Ovx rats was onl y 3.7%lower than that in Sham-operated rats(P>0.05),whereas the pQCT pure trabecular BM C in Ovx rats was 11.4%significant lo wer than that in Sham-operated rats(P<0.05).3)The correlation of total BMC measure d by DXA and pQCT was high(r=0.82,P<0.001).The correlation was found between DXA projectional area and pQCT volume (r=0.52,P<0.05),whereas no correlation was found between DXA areal BMD and pQCT volumetr ic BMD(r=0.14,P>0.05).A positive correlation was found between DXA BMC and DXA areal BMD(r=0.72,P<0.05),whereas no correlation was found between DXA projectional area and DXA a real BMD(r=0.32,P>0.05).A negative correlation was found between pQCT volume and pQCT total volumetric BMD(r=?0.57,P<0.05),whereas no correlation was found between pQCT total BMC and pQCT total volumetric BMD(r=0.30,P>0.05).Conclusion pQCT has higher measurement reproducibility and specialty than DXA in detecting faster bone loss induced by Ovx,particularly in the pure trabecular bone compartment.