Objectives: To investigate normal expression of PGP9.5 during dental development, and the effect of fluoride on it in secretion stage via animal model.
Methods: Pregnant SD rats (gestation 10 days) are randomly divided into 5 groups as E17, E19, PN1, PN5, PN9. Tissue of fetal rats' first mandibular molar germ of each group were obtained at gestation 17 (group E17), 19 days (group E19), and postnatal 1, 5, 9 days (group PN1, PN5, PN9). The PGP9.5 was detected by SABC immunohistochemical method. Pregnant SD rats (gestation 10 days) are randomly divided into 3 groups as control (double distilled water as drinking water), exp-group 1 (drinking water contain 200mg/L F-), exp-group 2 (drinking water contain 50mg/L F-). The first mandibular molar germ of fetal rats were obtained when gestation 21 days, fixed and embedded. Randomly, each group two of the molar germs were observed via TEM, and ten samples were observed via light microscope after HE and SABC immunohistochemical stain (anti PGP9.5).Positive and negative control was set in every SABC experiment. The results were quantitated by computer image analysis system, and the data of each group were compared by ANOVA.
Results: 1.During normal dental germ development, the PGP9.5-immunoreactive cells were observed at higher level in dental lamina, outer enamel epithelium, and dental sac in cap stage. As the tooth matured, it gradually decreased in ameloblasts. 2.The stain of PGP9.5 of the two experimental group is lower than control group.
Conclusion: The expression of PGP9.5 in the normal dental germ during development presents a specific pattern. Fluoride exposures of pregnant rats have a toxication effect on secretory ameloblasts of fetus rats. The expression of PGP9.5 in dental development is depressed by fluoride.