摘要：目的 明确全身给予辛伐他汀对大鼠牙齿移动后复发的影响,探讨辛伐他汀促进牙齿稳定的作用机制.方法 选用32只雄性Wistar大鼠,随机分成4组:对照组(0.9%NaCl)、低剂量组(2.5 mg·kg-1 辛伐他汀)、中剂量组(5.0 mg·kg-1 辛伐他汀)、高剂量组(10.0 mg·kg-1辛伐他汀),牵引其上颌第一磨牙向近中移动,持续21 d.实验组在加力装置去除前1 d开始,腹膜下注射辛伐他汀,阴性对照组注射生理盐水,每天1次,连续4周.分别在加力装置去除时及其后1、4周,测量上颌第一、第二磨牙间距离.取上颌第一磨牙及其牙周组织行组织学切片,HE染色及骨形成蛋白2(BMP-2)免疫组织化学染色,并进行图像分析和统计.结果 ①低、中、高剂量组大鼠牙齿移动复发距离均小于对照组(P＜0.05)、复发率明显低于对照组(P＜0.01),且剂量越小复发程度越小,低剂量组复发率最低(1、4周的复发率分别为26.81%、53.38%);②牙周组织中BMP-2表达量,低、中、高剂量组均高于对照组,差异有统计学意义(P＜0.001),低剂量组灰度积分增高最明显(P＜0.001);牙周组织中BMP-2表达,张力区略高于压力区,差异无统计学意义(P＞0.05).结论 在正畸牙齿移动后复发的过程中,辛伐他汀能有效抑制实验性牙移动后牙齿复发的程度,低剂量的辛伐他汀效果最明显.其作用可能是通过促进牙周组织中BMP-2蛋白的表达,加速成骨细胞活动,促进骨形成,促进移动后的牙齿稳定.%Objective To investigate the effect of systematic administration of simvastatin on the bone morphogenetie protein-2(BMP-2)expression in the periodontal tissue after rat tooth movement and on the relapse of tooth movement. Methods Orthodontic tooth movement of upper first molar was performed in 32 rats with coil spring for 21 days. The 32 rats were randomly allocated into 4 groups:negative control The simvastatin started to be administered to the experimental groups 1 day before appliances were removed,and once a day there after for 4 weeks. The negative control group received the isotonic saline only. The interdental distance between the first and second maxillary molars were measured,when appliances were removed, and 1 week and 4 weeks after tha. After the rats were sacrificed,sections of first maxillary molar and periodontal tissue were studied by immunohistochemistry. Results The number and percentage of relapse was lower in the three experimental groups than in the negative control group(P＜0.05,P＜0.01).The lower dose was given,the less relapse there was,with the lowerest dose resulting in lowest percentage of relapse(26.81% and 53.38%). BMP-2 expression in experimental groups was higher than in the negative control group,with the lowerest dose group showing the highest expression(P＜0.001). The BMP-2 expression on the tension side was slishtly stronger than that on the compression side(P＞0.05).Conclusions Systemie administration of simvastatin could decrease the extent of relapse of the orthodonticmoved tooth in rat, and the lower-dose of simvastatin seemed more effective. The possible mechanism for this may be that simvastatin functions by increasing the expression of BMP-2 in tlle periodontal tissue,accelerating the ossteoblast activity and promoting bone formation.