Effects of estrogen on marrow fat in ovariectomized rats assessed by water/fat MRI / 实用放射学杂志

ABSTRACT

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.