論文名稱:

神經生長因子及其接受器對牙胚發育之影響

 

The effects of nerve growth factor and its receptor on the development of tooth germ

研究生:

曾意芸  Yi-Yun Tseng

 

(以作者名查詢陽明大學館藏系統)

 

(以作者名查詢全國圖書書目資訊網)

指導教授:

楊世芳  Shih-Fang Yang

        學位類別:

碩士

        學校名稱:

國立陽明大學

系所名稱:

口腔生物研究所

          學年度:

84

          語文別:

中文

          出版年:

85

關鍵字:

牙醫  DENTIST

 

牙醫學  DENTISTRY

 

口腔  ORAL-HEALTH

 

胚胎發育期 

 

上皮組織 

 

間葉組統 

        論文頁數:

83

摘要:

在胚胎發育期,許多器官的形成都;是經由上皮與間葉組織間連續交互作用的結果, 牙齒也是其中之一,其中參與牙齒發育的上皮來自於外胚層的口凹上皮,而外間葉組織則起源於神經脊,最後這些外間葉組織之一部分將分化為形成牙本質的造牙本質細胞。已知神經生長因子,除了對神經脊衍生物包括感覺神經元及交感神經元的發育,分化與維持其存活是必須的之外,亦參與許多器官形態發生的過程,包括牙齒的發育,在上皮與間葉組織間扮演重要的調控角色。由免疫組織染色法的定位已知神經生長因子在牙齒發育的初始期與形庇發生期,及細胞分化期與後來神經開始支配牙齒時,皆能表現於牙胚細胞上。然而神經生長因子之表現於牙胚上,並不能代表其為使細胞產生反應的主畏角色,亦可能只是作為一個輔助因子。為了瞭解神經生長因子在牙胚表現的真正生理功能為何?將胚胎第十五天、第十七天及第十九天包含牙齒發育各期的牙胚取出,利用體外培養牙胚的方法,並於培養基中加入可中和神經生長因子的抗體以阻止神經生長因子的作用,最後以石蠟包埋經切片染色,而觀察所培養的牙胚其組織學上的變化。結果發現,喪失神經生長因子對牙齒之形成的影響並不明顯,但卻明顯地抑制了造牙本質細胞的分化,此結果指出神經生長因子可能負責造牙本質細胞的分化。但是無法知道此種作用是直接的,亦或是間接的。為了瞭解牙胚細胞是否產生神經生長因子之高親和力接受器TrkA,而證明神經生長因子的作用,以免疫組織化學染色法來觀察牙齒各發育期TrkA的表現,結果發現在造牙質細胞分泌前牙本質之前TrkA只能表現於牙器的各類細胞上,因此推測神經生長因子可能經由造釉細胞而間接控制造牙本質細胞的分化。

   
 

During embryogenesls, formation of many organs is the results of  epithelial-mesenchymal interactions. Epithelium and ectomensenchyme involved  in tooth development are derived from ectodermal stomatodeum epithelium and  cranial neural crest, respectively. Part of ectomesenchymal cells  differentiates into dentin-formative odontoblasts. Nerve growth factor (NGF),  a member of the target-derived neurotrophic factor family, is essential for  growth, differentiation and survival of neural crest-denved sensory neurons  and sympathetic neurons. In addition, it is involved in the process of  morphogenesis of many organs including tooth. Based on the studies by  immunohistochermcal localization, NGF, may serve as a signal transductor  during the initial period of tooth development, regulate the future crown  morphology, help differentiation of odontoblasts and support innervating nerve  fibers. However, expression of NGF in tooth germ may not be symbolic of a  major role to induce cell response; in contrast, it may be only an auxiliary  factor. To determine the actual function of NGF during tooth development, we  examined the effects of NGF neutralizing antibody on the tooth development  using an in vitro system. Tooth germs from day 15, day 17 and day 19 of the  pregnancy of S.D. rat, were cultured in an in vitro system at the presence of  NGF neutralizing antibody. The histologic changes of cultured tooth germs  were examined by paraffin section and staining to determine the actual  physiologic function of NGF in the tooth development. We found that NGF did  not affect the morphogenesis of tooth serms. However it was obviously cntical  for differentiation of odontoblasts. Our result indicated that NGF is mainly  responsible for differentiation of odontoblasts. To determine whether the  effects of NGF are direct or indirect on odontoblasts, we examined the  expression of the high-affinity receptor for NGF, TrkA, during tooth  development by imrnunohistochemistry. We found that TrkA was only expressed  in cells of dental organ before predentm secreted by odontoblasts. Therefore,  we suggest that NGF may control differentiation of odontoblasts by influence  the differentiation of ameloblasts indirectly.