雌激素和应力环境改变对骨质疏松大鼠下颌骨骨小梁结构的影响

目的: 探讨骨质疏松状态下由于牙齿缺失后应力环境的改变,导致下颌骨骨小梁结构的变化及补充雌激素对其变化的影响。方法: 用去势法建立骨质疏松的大鼠动物模型,8周后拔除大鼠单侧所有上颌磨牙,模拟下颌骨高低应力环境的变化,用骨组织形态计量学的方法观察骨质疏松组、雌激素治疗组和假手术对照组双侧下颌骨骨小梁的变化。结果: 骨质疏松组低应力侧比高应力侧的Tb.Ar、Tb.Wi明显降低(P<0.01),Tb.Sp明显增大(P<0.05);正常组和雌激素组无明显差异;雌激素组高应力侧、低应力侧的Tb.Ar与骨质疏松组同期相比增大(P<0.05)。结论: 高应力可减缓骨质疏松所引起的下颌骨骨小梁的吸收,低应力则可加速骨吸收;雌激素的补充治疗阻止了去势后大鼠下颌骨骨质的吸收,并抑制低应力环境下颌骨的进一步丢失,促进了骨形成。

Effects of estrogen on trabecular structure of mandibles in ovariectomized rats with changes of stress

Objective:To study the changes of stress on trabecular structure of mandible with lost teeth and effects on it by estrogen therapy. Methods: Animal models of osteoporosis were established by ovariectomized. 8 weeks later, the unilateral maxillary molars were extracted to establish high and low stress environment models of mandible. The changes of trabecular structure of bilateral mandibles were observed through bone histomorphometry in OP rats?E2 rats and Sham-OVX rats individually. Results: The Tb. Ar and Tb. Wi of low stress were lower than that of high stress in OP rats(P<0.01),Tb. Sp were higher(P<0.05);there was no difference between two sides in E2 and Sham-OVX rats;the Tb. Ar of two sides in E2 rats were higher than that of OP rats(P<0.05). Conclusions: High stress can inhibit trabecular bone resorption of mandible in ovariectomized rats, low stress can aggravate trabecular bone resorption of mandible; the bone resorption of osteoporotic mandible can be hindered by treatment of estrogen, inhibited bone loss with low stress, and increased bone volume.