孕鼠急性氟中毒对胎鼠牙胚造釉细胞影响的超微结构研究

The ultrastruction study of the effects of high doses of solidium fluoride on early secretory phase of ameloblast of lower first molar of tooth germs of fetus mouse in pregnant C57BL/6J

目的 :建立孕鼠急性氟中毒动物模型 ,观察孕鼠急性氟中毒对胎鼠牙胚造釉细胞的影响。方法 :孕 14d的C5 7BL/6J鼠 ,实验组腹腔注射 10mg/kg·wt氟化钠 ,对照组注射等量生理盐水。每天注射一次 ,直至孕 2 0d。麻醉下处死孕鼠 ,取出胎鼠 ,分离下颌第一磨牙 ,进行光镜超微结构切片观察。结果 :孕鼠大剂量的氟可以引起胎鼠造釉细胞下囊腔的形成。囊腔上方的造釉细胞严重受损 :核上区线粒体明显肿胀或溶解 ,囊壁的造釉细胞细胞质和细胞核显示各种程度改变 ,细胞核染色质浓缩 ,凋亡小体出现 ,胞浆从细胞中脱出进入囊腔 ,囊腔中可见细胞及细胞碎片 ,异常分泌的釉基质 ,吞噬细胞 ,托马斯突变短或消失 ,囊腔下方的釉质分泌减少或终止。结论 :大剂量的氟不仅能引起发育中的鼠牙胚氟斑牙的形成 ,而且也能引起胎鼠牙胚氟斑牙的形成。氟引起胎鼠牙胚造釉细胞下囊腔的形成 ,囊腔上方的造釉细胞是以细胞凋亡的方式进行退变的。

Objective:The aim of this study was to develop the experimental model of the developing fetus tooth germ. The effects of fluoride on lower first molar of fetus tooth germ were observed. Method:C57BL/6J mice,in gestation day 14(E-14),were given sodium fluoride by intraperitoneal injection at a dose of 10 mg per kgbody weight. This treatment was given once in a day from E-14 to fetuses were born(E-20).At this time fetus mice were killed, and the lower first molar(M1) from neonatal mice were prepared for Electron Microscopic Examination.Result:It was shown that ameloblasts of M1 of fetus mouse were injured heavily. The most prominent findings were swollen mitochondria in the early secretory ameloblasts and cysts formation between the ameloblasts and the enamel matrix. The ameloblasts of the cystic wall shown various degrees of cyloptasmic and nuclear alterations. Some cells displayed signs of apoptosis, as indicated by condensation of the chromation, appearance of apoptotic bodies. matrix secretion accumulated intracellularly. Electron Lucent material cell and cell fragments were found in the cystic lumina. Distortion of the Tomes processes and separation of the ameloblasts from the enamel surface could too be seen. Conclusion:This experiment Model was successful .Not only high doses of fluoride exposure resulted in dental fluorosis in the developing mouse tooth germs, but also in the developing fetus mice tooth germs in pregnancy C57BL/6J mice. Fluoride induced subameloblastic cysts in early secretory amaloblasts in M1 of fetuses mouse. The amaloblasts above the cysts seemed to follow the normal pattern of cell degeneration.