高正加速度对种植体周围牙槽骨组织成骨细胞功能的影响

Influence of high+Gz environment on osteoblast function in peri-implant alveolar bone tissue

目的采用动物模型观察高正加速度环境对种植体周围牙槽骨组织成骨细胞功能的影响。方法按随机数字表将30只新西兰白兔随机分为3周对照组、3周实验组、5周对照组、5周实验组、12周对照组、12周实验组6组,每组各5只。拔除其双侧下颌切牙后即刻植入种植体各1颗。术后1周开始每周将实验组动物高正加速度(+Gz)暴露3次,对照组不进行+Gz暴露,常规饲养。在术后3周(+Gz暴露2周)、5周(+Gz暴露4周)、12周(+Gz暴露4周+常规饲养7周)分别各处死1组实验组和1组对照组动物,取种植体周围骨质标本,采用实时荧光定量聚合酶链式反应(real-time polymerase chain reaction,RT-PCR)检测骨形成蛋白2(bone morphogenetic protein 2,BMP-2)、骨桥蛋白(osteopontin,OPN)及转化生长因子-β1(transforming growth factor-β1,TGF-β1)的mRNA表达情况。结果实验组和对照组BMP-2、OPN及TGF-β1的mRNA表达均在术后3周时最高,然后逐渐降低。术后3周时,实验组BMP-2、OPN及TGF-β1的mRNA表达明显低于对照组(BMP-2,P<0.01;OPN及TGF-β1,P<0.05);术后5周,实验组TGF-β1的mRNA表达明显低于对照组(P<0.05);12周时2组各指标表达差异无统计学意义。结论高正加速度环境能够降低BMP-2、OPN以及TGF-β1的表达,抑制成骨细胞的分化和成骨作用。

Objective To investigate the influence of a high+Gz environment on osteoblast function in the peri-implant alveolar bone tissue in an animal model.Methods Thirty New Zealand white rabbits were randomly divided into six groups(the control group of three weeks,five weeks,tweleve weeks,and the experimental group of three weeks,five weeks,and twelve weeks).Both sides of the mandible incisor of the rabbits were extracted and implanted with one implant in each socket immediately.After one week of rest,the experimental rabbits were exposed to a high+Gz environment three times a week while the control rabbits were normally fed.Rabbits of one control group and one experimental group were respectively sacrificed at three weeks(two weeks'+Gz exposure),five weeks(four weeks'+Gz exposure)and twelve weeks(four weeks'+Gz exposure and seven weeks'normal feeding)after surgery.The specimens were obtained for real-time polymerase chain reaction(RT-PCR)examination.Results The mRNA expressions of bone morphogenetic protein 2(BMP-2),osteopontin(OPN)and transforming growth factor-β1(TGF-β1)peaked at three weeks after surgery in both groups,but decreased gradually.At three weeks,the BMP-2,OPN and TGF-β1 mRNA expressions in the experimental group were significantly lower than those of the control group(BMP-2,P<0.01;OPN and TGF-β1,P<0.05).At five weeks,the TGF-β1 mRNA expression in the experimental group was still significantly lower than that of the control group(P<0.05).At tweleve weeks,there was no obvious difference between the two groups in the expressions of BMP-2,OPN and TGF-β1 mRNA.Conclusion A high+Gz environment can decrease the expressions of BMP-2,OPN and TGF-β1 while inhibiting differentiation and osteogenesis of osteoblasts.