不同大小的咀嚼负荷对炎性牙周组织骨代谢效应影响的实验研究

Effects of different masticatory loading on bone metabolism in periodontitis tissue

目的研究不同大小的咀嚼负荷对大鼠牙周组织炎性状态下的骨代谢效应的影响。方法利用高糖饮食+上颌第一磨牙龈沟注射脂多糖(lipopolysaccharide,LPS)的方法建立实验性牙周炎动物模型,随后将其随机分为LPS组与LPS+soft两组,分别用正常饲料与同配方定制软饲料饲喂,同期正常饲料喂养未建模的大鼠作为空白对照(control组)。采集大鼠上颌第一磨牙牙周膜及含磨牙上颌骨,分别用于real-time PCR和Micro-CT扫描、HE和TRAP染色等实验研究。结果Micro-CT结果显示相较于control组,LPS组和LPS+soft组大鼠上颌第一磨牙腭侧牙槽骨吸收明显,牙周膜纤维紊乱,炎细胞浸润,骨吸收陷窝形成,其中LPS组骨小梁厚度、数量等成骨指标显著低于LPS+soft组(P<0.05),而骨小梁间隙等破骨指标显著高于LPS+soft组(P<0.05)。real-time PCR结果显示,LPS+soft组和LPS组大鼠牙周膜中成骨相关标志因子Ⅰ型胶原(typeⅠcollagen,COL-1)、碱性磷酸酶(alkaline phosphatase,ALP)、Runt相关转录因子2(Runt-related transcription factor 2,RUNX-2)的mRNA表达水平与control组比较无显著差异(P>0.05),而破骨相关标志因子核因子κB受体激活因子配体(receptor activator of nuclear factor-κB ligand,RANKL)、组织蛋白酶K(cathepsin K,CTSK)、甲状腺旁腺激素样激素(parathyroid hormone-like hormone,PTHLH)的mRNA表达水平较control组显著升高(P<0.05),其中LPS组RANKL及CTSK的mRNA表达水平较LPS+soft组升高更为明显(P<0.05)。结论通过改变食物硬度的方法来探究不同力学载荷下实验性牙周炎大鼠牙周组织的骨代谢效应变化具有可行性;针对牙周炎患者,软质食物有助于减轻患牙牙周组织的破骨效应。

Objective To explore the effect of different masticatory loading on bone metabolism in periodontitis tissue in rats.Methods Eighteen male SD rats were induced to establish the experimental periodontitis model by high sugar water and lipopolysaccharide(LPS)every other day for 36 d.Then the rats were randomly divided into LPS group and LPS+soft group,and were fed with normal diet and customized soft diet with the same formula for 7 d respectively.And 9 male SD rats fed with normal diet in the same feeding environment were used as control group.The periodontium of maxillary first molar and maxilla were collected for real-time PCR,micro-CT scanning,HE and TRAP staining.Results Compared with control group,the palatal alveolar bone resorption of maxillary first molar in rats was obvious in LPS group and LPS+soft group.The periodontium fibers were disordered,and the inflammatory cell infiltration and bone resorption pits were formed in LPS group and LPS+soft group.The surface of alveolar bone was rougher in LPS group than in LPS+soft group,and the bone resorption was more obvious.The osteogenic indexes such as BV/TV,Tb.Th and Tb.N in LPS+soft group were significantly lower than those in LPS+soft group(P<0.05),and the osteoclastic indexes such as Tb.Sp and so on were significantly higher than those in LPS+soft group(P<0.05).Real-time PCR results showed that the mRNA expression levels of typeⅠcollagen(COL-1),alkaline phosphatase(ALP)and Runt-related transcription factor 2(RUNX-2)were not significantly diffe-rent between LPS group,LPS+soft group and control group(P>0.05),while the receptor activator of nuclear factor-κB ligand(RANKL),cathepsin K(CTSK)and parathyroid hormone-like hormone(PTHLH)mRNA expression levels were significantly higher in LPS group,LPS+soft group than in control group(P<0.05),and the mRNA expression levels of RANKL and CTSK in LPS group were significantly higher than those in LPS+soft group(P<0.05).Conclusion It is feasible to explore the changes of bone metabolism in periodontal tissue of experimental periodontitis rats under different mechanical loading by changing food hardness.For patients with periodontitis,soft food can help to reduce the osteoclast effect of periodontal tissue.