DSP developmental expression in rats tooth germs supplemented with fluoride

Although the fluorotic dentin morphology has been investigated, the point of dentinogenesis that leads to the fluorotic dentin formation as a result of fluoride hyper supplementation is still unclear. Objectives:Appearance and distribution of dentin sialoprotein (DSP) in 1 and 4 days-old molar tooth germs of rats supplemented with fluoride during the prenatal and postnatal life were investigated. Methods: Sperm-positive female rats were randomly divided into four groups, which from the fifth day of pregnancy were given: C- tap water, D- distilled water, Fl and Fh - water with low (11mg/l) and high (110mg/l) concentration of NaF respectively. Animals were fed with standard, trace fluoride diet. Immunohistochemical methods were applied to visualize DSP on fixed saggital sections. They were studied with BioRad µRadiance confocal system. Results:DSP-immunoreactivity in particular tooth layers differed in each water group and changed in age of the rat. In the P-1 group, the most intensive immunostaining was seen in the control group and decreased gradually in the low and high fluoridated as well as distilled water groups. The predentin and dentin revealed the strong DSP-immunoreactivity in the C, Fl and Fh groups while D-group staining expressed the moderate level. Odontoblasts were moderate stained in all groups but the control, where the staining was definitely stronger. The DSP-immunoreactivity in the dental papilla was stronger and comparable in the C and Fl groups than those in the D and Fh groups. In the P-4 groups the DSP-immunostaining in investigated layer increased in comparison to the younger animals except ameloblasts which were mostly completely DSP-immunonegative, but the differences between particular water-groups were not such evident. Conclusions:High fluoride supplementation during the prenatal and postnatal life exerts its adverse effect on the DSP expression indirectly by general animal development retardation.