To evaluat the effects of oophorectomy(OVX) and hysterectomy(HTX) on histomorphometric changes of trabecular and cortical bone, female (Sprague-Dawely)rats were subjected to sham surgery (conrol) (n=5), bilateral OVX(n=5), HTX(n=5), hystero
-oophorectomy(OHTX) (n=5). Subcutaneous injection of estradiol (E) (10 ug/kg) were given on the day of surgery and once per month in OVX(OVX+E) (n=5) and OHTX(OHTX+E)(n=5) rats. All rats were killed 2 months after operation , and their lumbar
spine
and
proximal tibia were processed decalcified fro quantitative bone histomorphometry using image analyzer. Trabecular bone volume was significantly reduced in OVX rates relative to that in control rats in spine(18.5% VS 32.2%, P=0.002) aknd in tibia
(13.5%
VS 28.3%). Cortical bone volume was also significantly reduced in OVX rats than those with control rats in spine and bibia respectively (20.7% VS 29.5%, p=0.05), (18.2% VS 30.6%, p=0.005). Trabecular and cortical volume were not significantly
different
between HTX and control rats. Compared to OVX+E rats, OHTX+E rats had significantly reduced trabecular bone volume in spine (21.4% VS 27.0%, P=0..2) and tibia (15.5% VS 24.0, p=0.004), but cortical bone volume were not different than those of
OHTX+E
rats, but cortical bone volume were significantly reduced in spine (18.4%^ VS 26.6%, p=0.04%) and in tibia(18.3% VS 25.0%, p=0.03).
These findings indicates that in OVX rats, the anabolic effects of E on trabecular bone is greater when the uterus has been preserved. From the above results, it might be suggested that OVX reduced not only trabecular but also cortical bone
volume.
Estrogen treatment prevent both trabecular andcortical bone loss. Hysterectomy has no direct effects on bone, but anabolic effects of estrogen on the vone are modulated by estrogen's uterotrophic activity.
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