摘要
乳牙根是人体中唯一能够进行生理性吸收的硬组织，其正常吸收是恒牙萌出的关键。破骨细胞（OC）和破牙细胞（OD）在此过程中发挥了重要的调控作用，现已明确有多种调控因子参与了破骨细胞和破牙细胞的增殖、分化、激活等骨吸收过程。
CK为番木瓜家族中的半胱氨酸蛋白酶成员，具有蛋白水解酶的特性，能够水解Ⅰ型胶原等骨基质蛋白，对破骨细胞、破牙细胞的形成和骨吸收有重要作用。FGFR1为成纤维细胞因子受体，能够与相应配体结合，调控成骨细胞及破骨细胞的增殖分化及骨形成。
本研究利用HE染色观察犬乳恒牙替换过程中组织形态的变化，TRAP染色观察破骨细胞、破牙细胞及其前体细胞的分布及数量变化，免疫组化方法检测犬乳恒牙替换过程中CK及FGFR1的表达。
结果表明：乳牙根吸收呈间断性，分静止期和活跃期，乳牙根吸收起始阶段组织形态稳定，晚期牙根及牙槽骨吸收活跃，同时骨改建明显。吸收活跃期破骨/破牙细胞及其前体细胞分布广泛，数量明显多于乳牙根稳定组、吸收早期组及恒牙列初期。
吸收活跃期破骨/破牙细胞内ＣＫ免疫组化强阳性，染色强度明显高于乳牙根稳定组、吸收早期组及恒牙列初期。恒牙胚发育过程中成釉细胞、成牙本质细胞及周围牙囊组织ＣＫ免疫组化染色阳性。表明ＣＫ作用于破骨细胞、破牙细胞、成釉细胞、成牙本质细胞及周围牙囊组织参与乳牙根的生理性吸收、恒牙萌出。
吸收活跃期破骨/破牙细胞、成骨细胞内FGFR1免疫组化强阳性，染色强度明显高于乳牙根稳定组、吸收早期组及恒牙列初期。恒牙胚发育过程中成釉细胞、成牙本质细胞及周围牙囊组织FGFR1免疫组化染色阳性。提示FGFR1作用破骨细胞、破牙细胞、成骨细胞、成釉细胞、成牙本质细胞及周围牙囊组织参与乳牙根的生理性吸收及恒牙的萌出。FGFR1一方面直接对破骨细胞及破牙细胞产生调控作用，另一方面通过成骨细胞间接对破骨细胞及破牙细胞产生调控作用。
The root of primary teeth is the hard tissue which can be resorbed under normalcircumstances only, regular absorption is the key to the permanent teeth eruption. Osteoclasts(OC) and odentoclast(OD) play important role in this process,and many factors have beenconfirmed to involve proliferation differentiation、activation of OC/OD.
CK is a novel member of the papain family of cysteine, which has an character ofproteolytic enzyme,can hydrolyze Collagen typeⅠof bone matrix proteins,and play a majorrole in formation of OC/OD and bone resorption. FGFR1is the receptor of FGF,which cancombine with the relevant ligand,and regulate and control the osteoblast (OB)and OC andbone formation.
In this research the changes of morphology were watched in the process of replacementof the primary and permanent teeth of the local dog through HE.the changes of the numberof OC/OD and its precursor cells were observe by TRAP.The expression of CK andFGFR1were detected by immunohistochemistry(IHC). The Result Show that the absorptionof primary tooth root is interrupted,contains resting stage and active phase, histomor-phological features was stable at the start, later primary tooth root and alveolar boneabsorption become active and bone remodeling shows lively. the number and distribution ofOC/OD and its precursor cells in active phase of absorption is larger and more extensivethan other groups.
CK in OC/OD in active phase of absorption show strong positive signals though IHCstains. positive signals is obviously stronger than the stable primary teeth group, earlyresorption of primary tooth group and early permanent teeth. In the process of developmentof permanent teeth, CK in ameloblast、odontoblast、dental follicle display strong positivesignals though IHC stains. Those imply that Ck take part in the primary teeth physiologicalabsorption and permanent teeth eruption though affecting OC/OD、ameloblast、odontoblast、dental follicle.
FGFR1in OC/OD、OB in active phase of absorption show strong positive signalsthough IHC stains. positive signals is obviously stronger than the stable primary teeth group,early resorption of primary tooth group and early permanent teeth. in the process of development of permanent teeth, FGFR1in ameloblast、odontoblast、dental follicle displaystrong positive signals though IHC stains. Those imply that FGFR1take part in the primaryteeth physiological absorption and permanent teeth eruption though affecting OC/OD、ameloblast、odontoblast、dental follicle. FGFR1regulate and control OC/OD directly andthough OB indirectly.
引文
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