Skeletal scintigraphic findings in endemic skeletal fluorosis

Skeletal Fluorosis: A Case of Inhalant Abuse Leading to a Diagnosis of Colon Cancer

Skeletal fluorosis is a long-term bone disease that develops when prolonged fluoride toxicity leads to osteosclerosis and bone deformities that result in crippling pain and debility. The disease is endemic to many countries due to environmental or industrial exposures. However, rare cases in the United States have been reported from various causes including heavy toothpaste ingestion, excessive tea consumption, voriconazole use, and inhalant abuse. Here, we present a case of a 41-year-old man who presented for weight loss and severe joint pains due to bony sclerotic lesions found on X-rays. Social history revealed that he had been recreationally inhaling compressed air dusters used for cleaning electronics. Owing to concern for malignancy, he underwent an extensive work-up which led to a diagnosis of colon cancer, but positron emission tomography/computed tomography (PET/CT) and bone biopsy were unexpectedly negative for metastatic bone disease. Further characterization of his lesions by skeletal survey led to a diagnosis of skeletal fluorosis secondary to inhalant abuse. As in this patient, the disease can be difficult for clinicians to recognize as it can be mistaken for various boney diseases such as metastatic cancer. However, once there is clinical suspicion for skeletal fluorosis, various tests to help confirm the diagnosis can include serum and urine fluoride levels, skeletal survey, and bone ash fluoride concentration. Treatment of skeletal fluorosis primarily involves cessation of fluoride exposure, and recovery can take years. Ultimately, further study is required to develop recommendations and guidelines for diagnosis, management, and prognosis of the disease in the United States.

Preliminary Analysis of MicroRNAs Expression Profiling in MC3T3-E1 Cells Exposed to Fluoride

Overexposure to fluoride from environmental sources can cause serious public health problems. Disrupted osteoblast function and impaired bone formation were found to be associated with excessive fluoride exposure. A massive analysis of microRNAs (miRNAs) was used to figure out the possible pathways in which fluoride affects osteoblast function. MC3T3-E1 cells were treated with 8 mg/L of fluorine for 7 days. Total RNA of cells was extracted, and their integrity and purity were tested. RNA samples were analyzed by using miRNA array, including miRNA labeling, hybridization, scanning, and expression data analysis to compare the profiling of miRNA expression between control and fluoride-treated group. Transcriptome analysis console and enrichment analysis calculated by miRSystem were used to predict target genes and collect miRNAs pathway maps. Forty-five upregulated and 31 downregulated miRNAs expression were found in the fluoride-treated group, and most of the verified miRNAs were mature. The KEGG pathway enrichment analysis searched out 36 pathways that scored more than 0.1. These pathways mainly included intracellular signaling, cytokines, metabolism, and cytoskeleton-related pathways. Among them, the Wnt, insulin, TGF-beta, hedgehog, VEGF, and notch pathways in osteoblasts were those mainly affected by fluoride treatment. These results have shown a number of higher level systemic pathways activated by overexposure of fluoride in osteoblastic cells and verified that fluoride affected the molecular crosstalk in the osteoblasts.

The clothes maketh the sign

Abstract

Pattern recognition is a key tool that enables radiologists to evoke certain diagnoses based on a radiologic appearance. In Shakespeare’s Hamlet, Polonius tells his son Laertes to dress well because “apparel oft proclaims the man”; this phrase is now expressed in modern parlance as “the clothes maketh the man”. Similarly in radiology, appearances are everything, and in the case of radiologic signs, occasionally “the clothes maketh the sign”. The radiologic signs described in this pictorial review resemble items of clothing, fabric types, headwear, or accessories and are found in the musculoskeletal, pulmonary, gastrointestinal, and genitourinary systems. These “clothing signs” serve as a useful visual trigger to help radiologists to identify particular disease entities.

Teaching Points

• Pattern recognition enables radiologists to evoke a diagnosis based on radiologic appearance.

• The radiologic signs described in this review resemble clothing, fabric, or accessories.

• These “clothing signs” serve as visual triggers that evoke particular disease entities.

Risk Assessment of Fluoride Intake from Tea in the Republic of Ireland and its Implications for Public Health and Water Fluoridation

The Republic of Ireland (RoI) is the only European Country with a mandatory national legislation requiring artificial fluoridation of drinking water and has the highest per capita consumption of black tea in the world. Tea is a hyperaccumulator of fluoride and chronic fluoride intake is associated with multiple negative health outcomes. In this study, fifty four brands of the commercially available black tea bag products were purchased and the fluoride level in tea infusions tested by an ion-selective electrode method. The fluoride content in all brands tested ranged from 1.6 to 6.1 mg/L, with a mean value of 3.3 mg/L. According to our risk assessment it is evident that the general population in the RoI is at a high risk of chronic fluoride exposure and associated adverse health effects based on established reference values. We conclude that the culture of habitual tea drinking in the RoI indicates that the total cumulative dietary fluoride intake in the general population could readily exceed the levels known to cause chronic fluoride intoxication. Evidence suggests that excessive fluoride intake may be contributing to a wide range of adverse health effects. Therefore from a public health perspective, it would seem prudent and sensible that risk reduction measures be implemented to reduce the total body burden of fluoride in the population.

Deterioration of teeth and alveolar bone loss due to chronic environmental high-level fluoride and low calcium exposure

OBJECTIVES

Health risks due to chronic exposure to highly fluoridated groundwater could be underestimated because fluoride might not only influence the teeth in an aesthetic manner but also seems to led to dentoalveolar structure changes. Therefore, we studied the tooth and alveolar bone structures of Dorper sheep chronically exposed to very highly fluoridated and low calcium groundwater in the Kalahari Desert in comparison to controls consuming groundwater with low fluoride and normal calcium levels within the World Health Organization (WHO) recommended range.

MATERIALS AND METHODS

Two flocks of Dorper ewes in Namibia were studied. Chemical analyses of water, blood and urine were performed. Mineralized tissue investigations included radiography, HR-pQCT analyses, histomorphometry, energy-dispersive X-ray spectroscopy and X-ray diffraction-analyses.

RESULTS

Fluoride levels were significantly elevated in water, blood and urine samples in the Kalahari group compared to the low fluoride control samples. In addition to high fluoride, low calcium levels were detected in the Kalahari water. Tooth height and mandibular bone quality were significantly decreased in sheep, exposed to very high levels of fluoride and low levels of calcium in drinking water. Particularly, bone volume and cortical thickness of the mandibular bone were significantly reduced in these sheep.

CONCLUSIONS

The current study suggests that chronic environmental fluoride exposure with levels above the recommended limits in combination with low calcium uptake can cause significant attrition of teeth and a significant impaired mandibular bone quality.

CLINICAL RELEVANCE

In the presence of high fluoride and low calcium-associated dental changes, deterioration of the mandibular bone and a potential alveolar bone loss needs to be considered regardless whether other signs of systemic skeletal fluorosis are observed or not.

High fluoride and low calcium levels in drinking water is associated with low bone mass, reduced bone quality and fragility fractures in sheep

Chronic environmental fluoride exposure under calcium stress causes fragility fractures due to osteoporosis and bone quality deterioration, at least in sheep. Proof of skeletal fluorosis, presenting without increased bone density, calls for a review of fracture incidence in areas with fluoridated groundwater, including an analysis of patients with low bone mass.

INTRODUCTION

Understanding the skeletal effects of environmental fluoride exposure especially under calcium stress remains an unmet need of critical importance. Therefore, we studied the skeletal phenotype of sheep chronically exposed to highly fluoridated water in the Kalahari Desert, where livestock is known to present with fragility fractures.

METHODS

Dorper ewes from two flocks in Namibia were studied. Chemical analyses of water, blood and urine were executed for both cohorts. Skeletal phenotyping comprised micro-computer tomography (μCT), histological, histomorphometric, biomechanical, quantitative backscattered electron imaging (qBEI) and energy-dispersive X-ray (EDX) analysis. Analysis was performed in direct comparison with undecalcified human iliac crest bone biopsies of patients with fluoride-induced osteopathy.

RESULTS

The fluoride content of water, blood and urine was significantly elevated in the Kalahari group compared to the control. Surprisingly, a significant decrease in both cortical and trabecular bones was found in sheep chronically exposed to fluoride. Furthermore, osteoid parameters and the degree and heterogeneity of mineralization were increased. The latter findings are reminiscent of those found in osteoporotic patients with treatment-induced fluorosis. Mechanical testing revealed a significant decrease in the bending strength, concurrent with the clinical observation of fragility fractures in sheep within an area of environmental fluoride exposure.

CONCLUSIONS

Our data suggest that fluoride exposure with concomitant calcium deficit (i) may aggravate bone loss via reductions in mineralized trabecular and cortical bone mass and (ii) can cause fragility fractures and (iii) that the prevalence of skeletal fluorosis especially due to groundwater exposure should be reviewed in many areas of the world as low bone mass alone does not exclude fluorosis.

The ameliorative effect of ascorbic acid and Ginkgo biloba on learning and memory deficits associated with fluoride exposure

Chronic exposure to fluoride causes dental and skeletal fluorosis. Fluoride exposure is also detrimental to soft tissues and organs. The present study aimed at evaluation of the effect of Ginkgo biloba and ascorbic acid on learning and memory deficits caused by fluoride exposure. Male Wistar rats were divided into five groups (n=6). Group 1 control. Groups 2 to 5 received 100 ppm of sodium fluoride over 30 days. Groups 3, 4 and 5 were further treated for 15 days receiving respectively 1% gum acacia solution, 100 mg/kg body weight ascorbic acid, and 100mg/kg body weight Ginkgo biloba extract. After 45 days, all animals were subjected to behavioural tests. The results showed that fluoride affected learning and memory. Fluoride causes oxidative stress and neurodegeneration, thereby affecting learning and memory. Ascorbic acid and Ginkgo biloba were found to augment the reversal of learning and memory deficits caused by fluoride ingestion.

Suppression of Sclerostin and Dickkopf-1 levels in patients with fluorine bone injury

Evidence has been accumulating for the role of Sclerostin and Dickkopf-1 as the antagonists of Wnt/β-Catenin signaling pathway, which suppresses bone formation through inhibiting osteoblastic function. To get deep-inside information about the expression of the antagonists in patients with fluorine bone injury, a case-control study was conducted in two counties in Hubei Province. Urinary and serum fluoride were significantly higher in patients with fluorine bone injury than in healthy controls. Additionally, patients with fluorine bone injury had significantly lower serum Sclerostin and Dickkopf-1 levels compared with healthy controls (P<0.001). Serum Sclerostin and Dickkopf-1 levels were significantly correlated with serum fluoride in all studied subjects (n=186). Low Sclerostin and Dickkopf-1 levels were associated with a significantly increased risk of fluorine bone injury. In conclusion, serum Sclerostin and Dickkopf-1 might be used as important markers of bone metabolism change and potential therapeutic targets to treat fluorine bone injury.

Amelioration of chronic fluoride toxicity by calcium and fluoride-free water in rats

The study was undertaken to explore the amelioration of chronic fluoride (F) toxicity (with low and normal Ca) in rats. The study was conducted in two phases. In phase I (6 months), seventy-six Wistar, weanling male rats were assigned to four treatment groups: normal-Ca (0·5 %) diet (NCD), Ca+F - ; low-Ca (0·25 %) diet (LCD), Ca - F - ; NCD +100 parts per million (ppm) F water, Ca+F+; LCD +100 ppm F water, Ca - F+. In phase II (reversal experiment, 3 months), LCD was replaced with the NCD. Treatment groups Ca+F+ and Ca - F+ were divided into two subgroups to compare the effect of continuation v. discontinuation along with Ca supplementation on reversal of chronic F toxicity. In phase I, significantly reduced food efficiency ratio (FER), body weight gain (BWG), faecal F excretion, serum Ca and increased bone F deposition were observed in the treatment group Ca - F+. Reduced serum 25-hydroxy-vitamin D3, increased 1,25-dihydroxy-vitamin D3 and up-regulation of Ca-sensing receptor, vitamin D receptor and S100 Ca-binding protein G (S100G) were observed in treatment groups Ca - F - and Ca - F+. In phase II (reversal phase), FER, BWG and serum Ca in treatment groups Ca - F+/Ca+F - and Ca - F+/Ca+F+ were still lower, as compared with other groups. However, other variables were comparable. Down-regulation of S100G was observed in F-fed groups (Ca+F+/Ca+F+ and Ca - F+/Ca+F+) in phase II. It is concluded that low Ca aggravates F toxicity, which can be ameliorated after providing adequate Ca and F-free water. However, chronic F toxicity can interfere with Ca absorption by down-regulating S100G expression irrespective of Ca nutrition.

Prevalence and aetiology of juvenile skeletal fluorosis in the south-west of the Hai district, Tanzania--a community-based prevalence and case-control study

INTRODUCTION

Fluorosis is endemic throughout the East African Rift valley, including parts of Tanzania. The aim of the study was to identify all cases of deforming juvenile skeletal fluorosis (JSF) in a northern Tanzanian village and to document the extent of dental fluorosis (DF).

METHODS

Door-to-door prevalence survey of all residents of the village. Residents were assessed for the presence of DF and JSF. Those with JSF and randomly selected controls from the same age range were further assessed for possible JSF risk factors.

RESULTS

The village had a population of 1435. DF was endemic within the population, being present in 911 (75.5%; 95% CI, 73.0-77.9) of dentate individuals who were examined (n = 1207). JSF was present in 56 of 1263 people examined, giving a prevalence of 4.4% (95% CI, 3.3-5.6) and was more common in males. Low body mass index, drinking predominantly well water 3 years previously, not being weaned on bananas, the use of fluoride salts in cooking during childhood and drinking more cups of tea per day were independent predictors of JSF.

CONCLUSIONS

Juvenile skeletal fluorosis is a common and preventable public health problem. Providing clean, low-fluoride, piped water to affected communities is of obvious health benefit.

Reversible skeletal disease and high fluoride serum levels in hematologic patients receiving voriconazole

We here investigate the occurrence of fluoride intake-associated alterations in patients with hematologic disease on triazol antifungal medication. Clinical, laboratory, and radiology data of overall 43 patients with hematologic malignancies taking voriconazole (n = 20), posaconazole (n = 8), and itraconazole (n = 4), and a hematologic patient control group (n = 11) are described. Bone pain and radiologic evidence of periostitis were exclusively observed in patients receiving long-term voriconazole. Cessation of treatment led to clinical improvement in all cases. In line with clinical evidence, fluoride serum concentration was elevated in patients receiving voriconazole (median, 156.5 μg/L; interquartile range, 96.8 μg/L; normal < 30 μg/L) but not in the other treatment groups (P < .001 for all comparisons vs voriconazole). We conclude that serum fluoride levels were elevated on average 5-fold above normal levels in hematologic patients receiving voriconazole. Clinically relevant skeletal disease was associated with renal insufficiency and above 10-fold elevated fluoride levels, and was reversible on termination of voriconazole treatment.

Evaluation of mandibular bone mineral density using the dual-energy X-ray absorptiometry technique in edentulous subjects living in an endemic fluorosis region

OBJECTIVES

Fluoride is one of the biological trace elements with a strong affinity for osseous, cartilaginous and dental tissue. The dental and skeletal effects of high fluoride intake have already been studied in the literature, but little is known about the effects of high fluoride intake on edentulous mandibles. The purpose of this study was to evaluate the effects of high fluoride intake on mandibular bone mineral density (BMD) measured by the dual-energy X-ray absorptiometry (DXA) technique in edentulous individuals with systemic fluorosis.

METHODS

32 people who were living in an endemic fluorosis area since birth and 31 people who were living in a non-endemic fluorosis area since birth (control group) participated in this study. Systemic fluorosis was diagnosed in the patients using the sialic acid (NANA)/glycosaminoglycan (GAG) ratio. The BMDs of the mandibles were determined by the DXA technique.

RESULTS

The serum NANA/GAG ratios in the fluorosis group were significantly lower than those in the control group (p < 0.001). There was also a statistically significant difference in mandibular BMD measurements (p < 0.05) between the systemic fluorosis and control groups, as measured by the DXA technique. Mandibular body BMD measurements were higher in the fluorosis group (1.25 ± 0.24 g cm(-2)) than in the control group (1.01 ± 0.31 g cm(-2)).

CONCLUSIONS

The results of the study showed that fluoride intake higher than the optimum level causes increased mandibular BMD in edentulous individuals. Further dose-related studies are needed to determine the effects of high fluoride intake on bony structures of the stomatognathic system.

Enduring fluoride health hazard for the Vesuvius area population: the case of AD 79 Herculaneum

BACKGROUND

The study of ancient skeletal pathologies can be adopted as a key tool in assessing and tracing several diseases from past to present times. Skeletal fluorosis, a chronic metabolic bone and joint disease causing excessive ossification and joint ankylosis, has been only rarely considered in differential diagnoses of palaeopathological lesions. Even today its early stages are misdiagnosed in endemic areas.

METHODOLOGY/PRINCIPAL FINDINGS

Endemic fluorosis induced by high concentrations of fluoride in water and soils is a major health problem in several countries, particularly in volcanic areas. Here we describe for the first time the features of endemic fluorosis in the Herculaneum victims of the 79 AD eruption, resulting from long-term exposure to high levels of environmental fluoride which still occur today.

CONCLUSIONS/SIGNIFICANCE

Our observations on morphological, radiological, histological and chemical skeletal and dental features of this ancient population now suggest that in this area fluorosis was already endemic in Roman times. This evidence merged with currently available epidemiologic data reveal for the Vesuvius area population a permanent fluoride health hazard, whose public health and socio-economic impact is currently underestimated. The present guidelines for fluoridated tap water might be reconsidered accordingly, particularly around Mt Vesuvius and in other fluoride hazard areas with high natural fluoride levels.

The genetic influence on bone susceptibility to fluoride

INTRODUCTION

The influence of genetic background on bone architecture and mechanical properties is well established. Nevertheless, to date, only few animal studies explore an underlying genetic basis for extrinsic factors effect such as fluoride effect on bone metabolism.

MATERIALS AND METHODS

This study assessed the effect of increasing fluoride doses (0 ppm, 25 ppm, 50 ppm, 100 ppm) on the bone properties in 3 inbred mouse strains that demonstrate different susceptibilities to developing enamel fluorosis (A/J a "susceptible" strain, 129P3/J a "resistant" strain and SWR/J an "intermediate" strain). Fluoride concentrations were determined in femora and vertebral bodies. Bone mineral density was evaluating through DEXA. Finally, three-point bend testing of femora, compression testing of vertebral bodies and femoral neck-fracture testing were performed to evaluate mechanical properties.

RESULTS

Concordant with increasing fluoride dose were significant increases of fluoride concentration in femora and vertebral bodies from all 3 strains. Fluoride treatment had little effect on the bone mineral densities (BMD) in the 3 strains. Mechanical testing showed significant alterations in "bone quality" in the A/J strain, whereas moderate alterations in "bone quality" in the SWR/J strain and no effects in the 129P3/J strain were observed.

CONCLUSION

The results suggest that genetic factors may contribute to the variation in bone response to fluoride exposure and that fluoride might affect bone properties without altering BMD.

Simultaneous exposure of excess fluoride and calcium deficiency alters VDR, CaR, and calbindin D 9 k mRNA levels in rat duodenal mucosa

Fluoride ingestion reduces intestinal calcium absorption; its molecular basis has not been studied. We studied the mRNA expression of calcium-sensing receptor (CaR), vitamin D receptor (VDR) and calbindin D 9 k (D 9 k) by northern blot analysis in the duodenal mucosa of rats. Weanling pups fed with chow diet containing adequate calcium (0.5% w/w) and drinking water (NaF < 1 ppm) served as controls (Group I) and were studied at 9 and 15 weeks. The pups, born to rats fed with a calcium-deficient diet (0.03%) and excess fluoride water (NaF 50 ppm), were continued on the same diet and water (Group II) until 9 weeks of age. Subsequently, Group II rats were divided into 4 subgroups; 3 subgroups with fluoride free water [II-A adequate calcium, II-B excess calcium (Ca 2%) and II-D calcium deficient], whereas II-C received fluorinated water and adequate calcium diet until 15 weeks. At 9 weeks, as compared to group-I, group-II had decreased VDR (P < 0.001) and D 9 k mRNA (P < 0.001), whereas CaR mRNA levels increased (P < 0.05). At 15 weeks, as compared to group-I, VDR mRNA further reduced in group II-D (P < 0.001) and II-C (P < 0.001), whereas it increased in group II-A. Removal of fluoride ingestion and calcium replenishment increased D 9 k mRNA expression, maximally in adequate calcium group (P < 0.001), while it was further reduced in group II-C (P < 0.001). CaR expression decreased significantly in all the groups. We conclude that excess fluoride reduces the mRNA levels of VDR and D 9 k in the duodenal mucosa of rats, thereby possibly reducing calcium absorption. Calcium supplementation with simultaneous fluoride removal improves their expression.

Effects of menopause on bone mineral density in women with endemic fluorosis

PURPOSE

The effects of menopause on bone mineral density (BMD) in women with endemic fluorosis were investigated.

MATERIALS AND METHODS

Eighty healthy Turkish women who lived in and around the city of Isparta were selected randomly and enrolled in this study. They were separated into four groups: group 1, 20 premenopausal women with regular menstrual cycles and endemic fluorosis; group 2, 20 postmenopausal women with endemic fluorosis; group 3, 20 premenopausal normal women constituting one control group; and group 4, 20 postmenopausal normal women constituting the other control group. Bone mineral density was measured in the lumbar spine and proximal femur using dual-energy x-ray absorptiometry.

RESULTS

In the premenopausal group, BMD values of vertebrae L2-L4 and Ward's triangle in women with endemic fluorosis were significantly greater than the respective values in women without endemic fluorosis (P = 0.024, P = 0.036). There were no differences between the groups in BMD values of the femoral neck (P = 0.156) and intertrochanteric area (P = 0.076). The BMD values of vertebrae L2-L4, the femoral neck, intertrochanteric area, and Ward's triangle in the postmenopausal women with endemic fluorosis were significantly greater than those of postmenopausal women without endemic fluorosis (P < 0.001, P = 0.015, P = 0.002, and P < 0.001, respectively). The BMD values of vertebrae L2-L4, the femoral neck, intertrochanteric area, and Ward's triangle in the premenopausal women with endemic fluorosis were significantly greater than those of postmenopausal women with endemic fluorosis (P = 0.010, P = 0.002, P = 0.004, and P = 0.010, respectively). The BMD values of the sites noted for the premenopausal controls were significantly greater than those of postmenopausal controls (P < 0.001, P < 0.001, P < 0.001, and P < 0.001, respectively).

CONCLUSIONS

Postmenopausal BMD values in both endemic fluorosis and controls were significantly less than premenopausal BMD values. Although the differences were less prominent in women with endemic fluorosis, menopause is still the major determinant of BMD in the spine and femur.

Hypocalcaemia in parental and F1 generation rats treated with sodium fluoride

The potential of sodium fluoride (NaF) to affect serum cations was assessed in the parent (P) and F1 generation rats. The sperm-positive pregnant experimental female rats received 40 mg NaF/kg body weight from day 6 of gestation either up to 21 days of lactation or only up to gestation followed by withdrawal of the treatment during lactation. On day 21 of lactation, blood samples were collected from P and F1 generation rats, allowed to clot and centrifuged at 1000 g for 10 min to obtain serum for analysis of various cations. Statistically significant increases in the concentrations of sodium and potassium in the serum of P and F1 generation rats were observed in the NaF-treated group; however, calcium and phosphorus concentrations were significantly lower than their vehicle control. Withdrawal of NaF treatment during lactation caused significant recovery in sodium, potassium and phosphorus concentrations in P and F1 generation rats as compared with NaF-treated animals. Although statistically significant recovery was not observed, the calcium concentration in P and F1 generation rats was comparatively higher on withdrawal of NaF treatment than in the NaF-treated group. It is concluded that the exposure of 40 mg NaF/kg body weight in pregnant female rats caused significant alterations in cationic concentration which recovered significantly (except calcium) on withdrawal of the treatment.

Modulation of fluoride toxicity in rats by calcium carbonate and by withdrawal of fluoride exposure

In order to assess the effect of calcium on the toxic effects of fluoride, adult female Wistar rats were treated with sodium fluoride (NaF, 500 ppm in drinking water) alone or in combination with calcium carbonate (CaCO3, 50 mg/ kg by oral intubation) daily for 60 days. Food, water and fluoride intake were measured daily for 60 days. Body weight gain, exploratory motor activity, rota-rod motor coordination, dental structure, activities of acetylcholinesterase (AchE, brain and skeletal muscle) and Na+ K+ ATPase (erythrocyte membrane and skeletal muscle) and the concentrations of protein (serum and skeletal muscle), calcium (serum) and fluoride (serum) were determined in these animals 24 hr after the last treatment. The same parameters were tested in another group, 60 days after withdrawal of NaF exposure (500 ppm in drinking water daily for 60 days). NaF treatment decreased food and water intake, reduced body-weight gain and impaired exploratory motor activity and rota-rod performance. Dental lesions, inhibition of the activities of AchE and N+ K+ ATPase and a decrease in the concentration of protein, and serum calcium were also observed in these animals. These effects were accompanied by a marked elevation of fluoride concentration in the serum. CaCO3 decreased the concentration of fluoride in the serum of NaF-treated animals. A decrease in serum fluoride concentration was found also after NaF withdrawal. A prevention of locomotor behavioural, biochemical and dental toxicities of fluoride was observed both in these groups. It is concluded that the dose of CaCO3 used in the present study has a potential to prevent the toxicity of fluoride by maintaining serum fluoride at a less toxic level. Further, the toxic effects of fluoride are reversible if its exposure is withdrawn for 2 months.

Vitamin D ameliorates fluoride-induced embryotoxicity in pregnant rats

We have evaluated the ameliorative effect of vitamin D on fluoride-induced embryotoxicity in pregnant rats. Oral administration of sodium fluoride (NaF; 40 mg/kg body weight) from days 6 to 19 of gestation caused, as compared with control, significantly lowered body weight, feed consumption, absolute uterine weight and number of implantations. As compared with the control, higher incidence of skeletal (presence of wavy ribs, 14th rib, dumbbell-shaped 5th sternebrae, incomplete ossification of skull) and visceral (subcutaneous haemorrhage) abnormalities was recorded in the foetuses of fluoride-treated pregnant rat. Vitamin D (2 ng/0.2 ml olive oil/animal/day po) treatment significantly ameliorated the fluoride-induced reductions in body weight, feed consumption and absolute uterine weight. As compared with fluoride-treated alone, the total percentage of skeletal and visceral abnormalities observed in foetuses was significantly lowered in fluoride plus vitamin D-treated animals. These findings suggest that vitamin D treatment significantly reduced the severity and incidence of fluoride-induced embryotoxicity. The ameliorative effect of vitamin D against skeletal and visceral abnormalities could be due to stimulation of intestinal absorption of calcium and phosphate, thus raising the plasma calcium and phosphate concentrations.

Calcium preventing locomotor behavioral and dental toxicities of fluoride by decreasing serum fluoride level in rats

Spontaneous motor activity, rota-rod performance (motor co-ordination), body weight gain, food intake, activities of total cholinesterase (blood) and acetylcholinesterase (brain), and dental structure were determined in adult female rats treated with a very high dose of sodium fluoride (500 ppm in drinking water) alone and in combination with calcium carbonate (50 mg/kg body weight by oral intubation) for 60 days. The concentration of fluoride and calcium were measured in the serum of these animals. Administration of sodium fluoride with drinking water produced both behavioural and dental toxicities and not lethality in the present study. A suppression of spontaneous motor activity, a shortening of rota-rod endurance time, a decreased body weight gain and food intake, a suppression of total cholinesterase and acetylcholinesterase activities and dental lesion were observed in test animals. Serum fluoride concentration was raised markedly and that of calcium was decreased in these animals. The effects of sodium fluoride were prevented significantly when animals received calcium carbonate along with sodium fluoride. Serum fluoride content was decreased and that of calcium was restored to control level in these animals. These results indicate that calcium prevents not only fluoride-induced hypocalcemia but also the locomotor behavioral and dental toxicities of fluoride by decreasing bioavailability of fluoride.

Effects of sodium fluoride on locomotor behavior and a few biochemical parameters in rats

Spontaneous motor activity and motor coordination were tested in adult female rats after treating with sodium fluoride at 20 or 40 mg/kg dose level daily for 60 days, using an activity chamber and a rota-rod apparatus, respectively. Total protein concentrations were determined in skeletal muscle, liver and serum of similarly treated animals. The activities of total cholinesterase and acetylcholinesterase were determined in blood and brain regions, respectively. Sodium fluoride treatment suppressed spontaneous motor activity. But no change was observed in the motor coordination of these animals. Tissue and serum protein concentrations were decreased. Cholinesterase activity was decreased in the blood and not in brain regions. A failure of sodium fluoride to impair motor coordination indicated that neuromuscular function required for a forced task was not deteriorated in these animals, although skeletal muscles were deprived of protein and blood cholinesterase activity was suppressed. A suppression of spontaneous motor activity suggests that fluoride has, by a central action, inhibited motivation of these animals to exhibit locomotor behavior. A cholinergic mechanism through a change in the activity of acetylcholinesterase may not account for this effect, since sodium fluoride treatment did not alter the activity this enzyme in brain regions. However, an involvement of monoamines may be proposed in view of previously reported finding that excessive fluoride intake has decreased the concentrations of 5-hydroxyindoleacetic acid and increased that of norepinephrine in rat brain.