Role of Prostaglandins on Resorption of Deciduous Teeth during Teeth Exchange in Rabbits

本研究旨在证实PGE2是否与生理性根吸收有关。我之前的研究表明，家兔乳牙上切牙的吸收开始于出生后第9天，吸收发生在3个阶段：(1)早期（9-13天），此时破牙细胞吸收活跃；(2)休眠期（15-21天）；(3)最后阶段（23-25天），牙细胞和炎性细胞重新吸收。在这项研究中，64只幼兔使用。对照组给予生理盐水注射，治疗组分别于牺牲前9hr和3hr注射10.0 mg/kg吲哚美辛。切除上颌，仔细去除根吸收组织（RRT），分别于第5、9、13、17、21、25天采用[^<125>I] PGE2-RIA试剂盒测定其PGE2水平。同时，观察口腔硬腭黏膜（OMP） PGE2水平。结果表明：PGE2浓度（平均<正负>S.D.）RRT的pg / mg wet.tiss)。对照组446 <加减> 419年5天,3751 <加减> 2454年9天,748 <加减> 504年13天,180 <加减> 19在17天,253 <加减> 128年21天,1520 <加减> 398年25天,在对照组和OMP 87 <加减> 98年5天,242 <加减> 377年9天,25日<加减> 18在13天,60 <加减> 47在17天,362 <加减> 131年21天,1168 <加减> 1164年25天,分别。对照组第9、13、25 d时PGE2水平均高于第5、17、21 d时（p<0.05）。RRT组PGE2在第9、13天高于OMP组（p<0.05）。除第5天外，治疗组PGE2在RRT和OMP中均低于对照组（p<0.05）。这些结果强烈提示PGE2可能是牙髓经典根吸收发生的化学介质

The study aimed to confirm whether PGE2 had any connection with physiological root resorption. My previous study showed that resorption of deciduous upper incisors in rabbits started on the 9th day postnatally and that the resorption occured in 3 stages : (1) early stage (9-13 days), where there was active resorption by odontclasts ; (2) resting stage (15-21 days) ; and (3) final stage (23-25 days), where resorption reoccured by odontclasts and inflammatory ceels. For this study, 64 young rabbits used. The control groups were injected with normal salin, and the treatment groups were injected with 10.0 mg/kg indomethacin at 9hr and 3hr before sacrifice. The maxillae were excised, and the root-resorbing tissue (RRT) were carefully removed and the PGE2 level of them were measured by RIA using [^<125>I] PGE2-RIA kit at 5,9,13,17,21 and 25 days, respectively. Additionally, the level of PGE2 of the oral mucosa of hard palate (OMP). The resuls were as follows :The concentration of PGE2 (mean<plus-minus>S.D.pg/mg wet.tiss.) of RRT in control groups were 446<plus-minus>419 at 5 days, 3751<plus-minus>2454 at 9 days, 748<plus-minus>504 at 13 days, 180<plus-minus>19 at 17 days, 253<plus-minus>128 at 21 days and 1520<plus-minus>398 at 25 days, and those of OMP in control groups were 87<plus-minus>98 at 5 days, 242<plus-minus>377 at 9 days, 25<plus-minus>18 at 13 days, 60<plus-minus>47 at 17 days, 362<plus-minus>131 at 21 days and 1168<plus-minus>1164 at 25 days, respectively. PGE2 levels at 9,13 and 25 days were greater than at 5,17 and 21 days in control groups (p<0.05). PGE2 in RRT was higher at 9 and 13 days than in OMP (p<0.05). Except at 5 days, PGE2 in treatment group was always lower than in control group, in both RRT and OMP (p<0.05). These results strongly suggest that PGE2 can possibly act as a chemical mediator of odontoclasic root resorption occurr