High-resolution Micro-CT evaluation of mid- to long-term effects of estrogen deficiency on rat trabecular bone.
OBJECTIVE
Previous studies have shown dramatic short-term bone loss following ovariectomy. The purpose of this study was to evaluate mid- to long-term effects of estrogen deficiency on microarchitecture of tibial trabecular bone using a high-resolution microcomputed tomography (Micro-CT).


METHODS
Twenty-eight female rats were divided into two equal groups: ovariectomized (OVX, n = 14) and sham-operated (SOVX, n = 14), which in turn were divided into two equal subgroups (euthanized either 6 or 16 weeks after surgery). The left tibia of each animal was scanned with a high-resolution micro-CT (Skyscan 1072 micro-CT system; SkyScan, Aartselaar, Belgium). The Micro-CT system used an X-ray CCD-camera with a cooled 1024 x 1024-pixel 12-bit sensor.


RESULTS
Ovariectomy significantly decreased the ratio of bone volume:tissue volume (-42% at 6 weeks and -69% at 16 weeks) and trabecular thickness (-13% at 6 weeks and -30% at 16 weeks), while significantly increasing trabecular separation (+73% at 6 weeks and +100% at 16 weeks) and structure model index (+15% at 6 weeks and +48% at 16 weeks), when compared with SOVX, from 6 to 16 weeks.


CONCLUSIONS
Based on the experimental results, there are alterations of trabecular microarcihtecture in the tibia following mid- and long-term estrogen deficiency. More rod-shaped trabeculae are formed with increasing duration of estrogen deficiency. The high-resolution micro-CT imaging system is useful to evaluate the mid- to long-term trabecular changes seen with estrogen deficiency or osteoporosis.
Division of Oral and Maxillofacial Radiology, Department of Oral & Maxillofacial Pathology, Medicine, and Surgery, Temple University School of Dentistry, 3223 N Broad Street, Philadelphia, PA 19140, USA.
Jie
J
Yang
Son M
SM
Pham
Deborah L
DL
Crabbe
D000818:Animals; D001842:Bone and Bones / Q000000981:diagnostic imaging*; D004967:Estrogens / Q000172:deficiency; D005260:Female; D008852:Microradiography; D010024:Osteoporosis / Q000000981:diagnostic imaging* / Q000209:etiology; D010052:Ovariectomy; D051381:Rats; D011914:Rats, Inbred BN; D011917:Rats, Inbred Lew; D013977:Tibia / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000379:methods
D004967:Estrogens