不同浓度尼古丁对种植体骨愈合的影响

摘要

目的：探讨不同浓度的尼古丁干预，对种植体周围骨组织的愈合情况和骨保护素（OPG）及骨形成蛋白2（BMP-2）表达情况的影响。方法：选取24只3月龄SD大鼠，雌雄不限，随机数表法分为实验组和对照组，尔后分别采用不同浓度（2mg/kg、0.2mg/kg、0.02mg/kg）的尼古丁和等量生理盐水干预，每天2次背部皮下注射。2周后，大鼠左右胫骨近骺端均植入表面喷砂蚀刻处理的钛合金种植体，并继续施加干预因素。种植后第2、4周分别行X线、 CT、电镜观察和qRT-PCR检测。采用SPSS17.0软件对数据进行单因素方差分析（One-Way ANO-VA test），组内比较行t检验。结果： X线灰度值显示，除高浓度尼古丁组（HDN）与对照组存在差异（P＜0.05）外，各组组间差异不明显。 CT-BMD值观察，在高浓度或长期尼古丁刺激下种植体周围骨组织矿化程度明显低于对照组，且实验各组差异明显（P＜0.05）。实时荧光定量PCR结果显示，2周时随着尼古丁干预浓度的增加，种植体周围基因表达量逐渐降低，且与对照组差异明显（P＜0.05），仅低尼古丁浓度（LDN）组与对照组中的BMP-2的表达无明显差异（1/0.93±0.17， P＞0.05）；实验第4周，各尼古丁组的基因表达量均出现下调（P＜0.05）。扫描电镜（SEM）观察发现，随着尼古丁浓度和干预时间的增加，骨小梁结构发生改建障碍，多呈纤维骨或编织骨，骨基质分布不均匀且纤维结构排列紊乱无定向。结论：尼古丁对种植体周围骨愈合的抑制作用可能与其下调相关骨活性基因的表达关系密切，且抑制作用受尼古丁干预时间和浓度的影响明显。%Objective: To study the healing conditions of the soft and bone tissue around the implant and the expression of the OPG and BMP-2 under intervened by different concentration of nicotine. Methods:Twenty four SD rats were equally randomly applied for High-dose group, Middle-dose group, Low-dose group and Control group, and intervened with 2mg/kg/bid, 0.2mg/kg/bid, 0.02mg/kg/bid and saline for 2 weeks. Then the two tibia of the rats were implanted by the titanium implant with the surface acid-sandblasting process under continuous nicotine-intervened. The specimens were observed by X-ray, CT, qRT-PCR and SEM ( scanning electron microscope) at the end of 2nd and 4th weeks. Datum analyzed with SPSS17.0 One-Way ANOVA test and comparison in group analyzed with T test. Result:The X-ray shows that there is no significant difference in group, except the HDN and control group. The CT images and BMD show that the nicotine groups are significant lower than control group, and there is significant difference in nicotine groups. The qRT-PCR show that the expression of the BMP-2 and OPG is gradual reduced as the increasing dose of nicotine during the two weeks, but there is no difference between the LDN and the control group (1/0.93±0.17), and the genes expression of the groups are sharp reduced in the later time. The SEM shows that the trabecular bone is inhibited and the woven bone is becoming, the bone matrix is distribution and disordered arrangement as the level and the intervened time of nicotine increased. Conclusion: There is great relationship between the inhibition of osseointagration of peri-implant and the down-regulate the expression of osteoinductive activity genes, and the effect has obvious time and concentration dependence.