MR I水/脂分离技术评价雌激素对骨质疏松骨髓脂肪的作用  

Effects of estrogen on marrow fat in ovariectomized rats assessed by water/fat MRI

作　　者：李雪峰[1] 李冠武[1] 常时新[1] 周蕾[1] 陈瑶[1] 鲍虹[1] 

机构地区：[1]上海中医药大学附属岳阳中西医结合医院医学影像科,上海200437

出　　处：《实用放射学杂志》2015年第3期480-483,497,共5页Journal of Practical Radiology

基　　金：国家自然科学基金项目资助（81202809,81373856）。

摘　　要：目的：探讨 MRI水/脂分离成像评估雌二醇（E2）对大鼠原发性骨质疏松（OP）模型骨髓脂肪含量变化规律。方法27只12周龄雌性 SD大鼠随机均分为假手术组（SHAM）、去卵巢组（OVX）及 OVX＋E2。分别在基线及术后6、12周行DXA及 MRI水/脂分离成像,获取骨密度（BMD）及骨髓脂肪分数（MFF）。股骨远端 HE 染色定量骨髓脂肪细胞。结果 OVX组 MFF呈时序性增高而BMD呈时序性降低。第6、12周时,OVX组 MFF较基线时分别增高40.0%、69.4%（P 均＜0.001）。第6 周始,SHAM与 OVX组间 MFF有显著性差异,而组间BMD直至第12周时才有统计学差异（P 均＜0.001）。OVX组骨髓脂肪细胞大小、密度及面积百分比较 SHAM组分别增高29.5%、57.3%、163%,较 E2分别增高23.3%、68.6%、167%（P 均＜0.001）。E2组 MFF值及脂肪细胞参数与 SHAM组无统计学差异。MFF与腰椎BMD（r=-0.668）及股骨 BMD（r=-0.735）负相关,而与脂肪细胞面积（r=0.819）、直径（r=0.598）及密度（r=0.743）存在正相关,P均＜0.01。结论 MRI水/脂分离成像可动态评估骨髓脂肪含量, E2抑制骨吸收同时可能通过调控骨髓脂肪含量起作用。Objective To study the effects of 17β-estradiol （E2）on marrow adiposity in ovariectomized （OVX）rats using water/fat MRI.Methods Twenty-seven female SD rats were divided equally into SHAM,OVX and OVX＋E2 groups.BMD and marrow fat fraction （MFF）were measured at baseline and 6,12 weeks postoperation.Marrow adipocyte were evaluated by HE.Results OVX rats showed a significant increase in MFF over time,with an increase in MFF （by 40.0%）at week 6 from baseline ,and maintained until week 12 （by 69.4%）.Compared with SHAM group,MFF in OVX group was markedly increased at week 6 but a reduction in BMD first detected at week 12.OVX rats had substantially higher adipocyte size （by 29.5%）,density （by 57.3%）and volume （by 163%）than that in SHAM rats.E2 treatment prevented OVX-induced bone loss and rescued marrow adiposity to the levels of SHAM rats.MFF was inversely related to vertebral BMD（r=-0.668）and femoral BMD （r=-0.735）but positively associated with percent adipocyte volume（r=0.819）,size（r=0.598）and density（r=0.743,allP〈0.01）.Conclusion Water/fat MRI may be an useful technique to quantify marrow fat content.By regulating the amount of marrow fat,this effect may contribute to the beneficial effect of E2 on bone mass.

关 键 词：骨质疏松 雌二醇 骨髓脂肪 水/脂分离 

分 类 号：R681[医药卫生—骨科学] R445.2[医药卫生—外科学]