Chronic Exposure to Fluoride During Gestation and Lactation Increases Mandibular Bone Volume of Suckling Rats.

We aimed to investigate the effect of maternal exposure to NaF on mandibular bone microarchitecture and phosphocalcic plasma parameters of the offspring. For this purpose, 10-, 15-, and 21-day-old pups (n = 6-8 per group) from two groups of mothers, control and NaF 50mg/L treated dams, were used. Plasma calcium (Ca) and phosphorus (P) levels and alkaline phosphatase activity (ALP) were measured. Fluoride concentration (F-) in bone and in stomach content was measured using potentiometry after isothermal distillation. Morphometric, histological, and histomorphometric analyses of the jaw bones were performed. Plasma Ca and P levels and ALP activity increased in 10-day and decreased in 21-day-old pups from NaF-treated mothers. Fluoride concentration in stomach content samples of 15- and 21-day-old nursing pups from mothers exposed to NaF in their drinking water was higher compared to that observed in control dam offspring. Mandibular F- content was higher in 21-day-old pups born to F--exposed dams compared to those observed in age-matched control pups. Mandibular area increased in 21-day-old pups born to treated mothers as compared to controls. Mandibular bone volume BV/TV (%) was higher in offspring from NaF-exposed dams than in controls at all the studied times. The increase in bone volume after exposure to F- was concomitant with the increase in trabecular thickness and the decrease in trabecular separation. Altogether, our results showed that exposure to NaF during gestation and lactation increased mandibular area and bone volume of pups, with concomitant changes in phosphocalcic parameters associated with the bone modeling process.

Prenatal Exposure to Continuous Constant Light Alters Endochondral Ossification of the Tibiae of Rat Pups.

UNLABELLED: Clinical and experimental studies suggest that prenatal exposure to stress can impact the growth and development of offspring. The effect of prenatal exposure to constant light, applied as a chronic stressor, on endochondral ossification of the tibiae of 3-day-old and 15-day-old pups was histomorphometrically evaluated. Pregnant rats were divided into 2 groups: mothers chronically exposed to a 12:12-hour light/light cycle (LL) and control mothers maintained on a 12:12-hour light/dark cycle on days 10-20 of pregnancy. On postnatal days 3 and 15, the pups were weighed and euthanized. The tibiae were resected and histologically processed to obtain sections for hematoxylin and eosin staining (HE) and tartrate-resistant acid phosphatase (TRAP) histochemistry, in order to perform histomorphometric determinations. The data were statistically analyzed. A significant decrease in hypertrophic cartilage thickness was observed in the tibiae of the 3-day-old (LL: 0.134 ± 0.02 vs. CONTROLS: 0.209 ± 0.023 mm; p < 0.01) and 15-day-old (LL: 23.32 ± 3.98 vs. CONTROLS: 22.96 ± 1.93 mm; p < 0.05) prenatally stressed pups. The subchondral bone volume was significantly lower in the tibiae of the 3-day-old LL pups (38.83 ± 6.14%) than in the controls (62.83 ± 10.67%; p < 0.01). The decrease in subchondral bone volume and hypertrophic cartilage thickness shows that the normal growth process of the tibia is impaired in prenatally stressed pups.