Prostaglandin E₂ 投与によるラット臼歯の実験的移動時における歯根膜の細胞動態に関する研究

抄録

The purpose of this study was to ascertain that local application of prostaglandin E₂ (PGE₂) produced some effects on the proliferative activity of the cell and collagen synthesis in rat periodontal membrane during tooth movement. According to Waldo’s description, an orthodontic elastic band was inserted between the upper first and second molar of 7 to 9 week-old male wister rats. After insertion of the elastic band experimental group,10μg/50μl of PGE₂ was injected locally into the mucogingival around the first molar. The control group was injected with 50μl of saline for 3,7, and 14 days. Twenty minutes before sacrifice, each animal received an intraperitoneal injection of 74 kBq/g of ³H-proline. After the sacrifice, teeth and supporting tissue of the upper molar were decalcified, embedded, sectioned, and autoradiographed to observe staining of hematoxylin-eosin,the silver staining of nucleolar organizer regions (Ag-NORs). On the 3rd day’s pressure side after tooth movement, the control group had about twice as many cells with one and more Ag-NORs as the experimental group. Both on pressure side and tension side on the 3rd day after experimental tooth movement, silver grain labelled ³H-proline specifically increased compared with that of the control group. As to the number of osteoclast, the experimental group specifically increased compared with that on the pressure side of the control group on the 3rd and 7th days.

All the above findings demonstrated that treatment with PGE₂ inhibited the proliferation of periodontal fibroblasts and activated collagen synthesis concerning the remodeling by the activated osteoclast in the begining of tooth movement in rats.