新型有序纳米介孔生物玻璃充填骨质疏松区域骨缺损对周围骨密度的影响

Bone Mineral Density of the Surrounding Bone Tissues after Mesoporous Bioactive Glass Implantation in Bone Defects of Osteoporotic Area in Rabbits

目的：观察新型有序纳米介孔生物活性玻璃（mesoporous bioactive glass,MBG）充填骨质疏松区域骨缺损对周围骨密度（bone mineral density,BMD）的影响,探讨MBG局部充填在骨质疏松骨折治疗中的意义。方法：将20只成年新西兰兔用高分子石膏管型固定左后肢6周,在股骨髁制造直径为5 mm的包裹性骨缺损;按照随机数字表法分成MBG组（n=10）和对照组（n=10）;MBG组充填MBG材料,对照组不做任何处理;继续用石膏固定左后肢4周后拆除石膏。在石膏固定后即刻（T0）、2周（T1）、4周（T2）、6周（T3）以及骨缺损术后即刻（T4）、2周（T5）、4周（T6）、6周（T7）、8周（T8）、10周（T9）和12周（T10）时,用定点法监测双后肢股骨髁和胫骨平台特定区域的BMD值,在T4、T7和T10时进行X线摄片,比较各组间各部位的BMD值。结果：（1）左股骨髁和胫骨平台的BMD值在T3时较T0时分别下降0.080 g/cm2（占T0时BMD值的21.3%,P〈0.01）和0.075 g/cm2（占T0时BMD值的20.7%,P〈0.01）,证实新西兰兔左膝废用性骨质疏松动物模型建立成功;（2）骨缺损术后定点法BMD值监测（T4-T10）发现,MBG组和对照组在T4-T6时BMD值呈进行性下降,在T6-T10时BMD值呈进行性上升。MBG组左股骨髁BMD值在T4、T6、T8、T10时均明显高于同时间点对照组（P〈0.01）,左胫骨平台BMD值与对照组比较差异无统计学意义;（3）X线片显示,T7和T10时MBG组较对照组骨缺损处骨量更多,骨质更致密,股骨髁塌陷变形不明显。结论：用MBG充填骨质疏松区域骨缺损能诱导周围骨组织新骨形成,能有效增加BMD,提高骨强度,这对防治骨质疏松性骨折有积极意义。

Objective：To study the influence of mesoporous bioactive glass（MBG）implantation in bone defects of osteoporotic area on bone mineral density（BMD）of the surrounding bone tissues,in order to investigate the therapeutic effects of MBG implantation on osteoporotic fractures.Methods：Left hind limbs of twenty healthy adult New Zealand rabbits were fixed with plaster for 6 weeks.They were randomly divided into MBG group（MBG was implanted were made in the defects）and control group after 5 mm encapsulated bone defects were made in the center of left hind femoral condyle by electrical drill.In MBG group,MBG was implanted in the defects,while the control group received no treatment.Rabbits in both groups were fixed with plaster for another 4 weeks.The BMD of bilateral hind femoral condyle and tibial plateau were measured by the site-directed method immediately after fixation（T0）and at 2 weeks（T1）,4 weeks（T2）,6 weeks（T3）after fixation.They were also measured immediately after operation（T4）and at 2 weeks（T5）,4 weeks（T6）,6 weeks（T7）,8 weeks（T8）,10 weeks（T9）and 12 weeks（T10）after operation.X-ray of bilateral hind limbs was taken at T4,T7 and T10.The results were compared between the two groups.Results：（1）The BMD values of bilateral hind femoral condyle and tibial plateau at T3 had decreases of 0.080 g/cm2（21.3% of the BMD value at T0,P〈0.01）and 0.075 g/cm2（20.7% of the BMD value at T0,P〈0.01）,which showed that the disuse osteoporotic models of left hind limbs have been prepared successfully by T3;（2）The BMD values of left hind femoral condyle decreased from T4 to T6,but increased from T6 to T10.The BMD values of left femoral condyle in MBG group at T4~T10 were higher than those in control group（P〈0.01）,while there was no significant difference in the BMD values of left tibial plateau between MBG group and control group;（3）The results of X-ray showed that there were more bone quantity and denser bone quality of bone defects at T7 and T10 of MBG group than those in control group,and there was no obvious concave deformation in femoral condyle in MBG group.Conclusions：MBG implanted in bone defects of osteoporotic area can induce new bone formation in the surrounding areas,increase BMD effectively,and improve the bone strength,which are helpful for the prevention and treatment of osteoporotic fractures.