Effect of Sodium Fluoride Administration to Rats on Bone Phosphorous Content and Phosphatemia

Abstract

Fluoride (F) has a known mitogenic effect on bone cells. The daily administration of 40 micromol NaF per 100 g of body weight (bw) increases bone mass in rats. Nevertheless, the quality and composition of bone formed under F stimulus is still matter of study. The objective of this work was to investigate the effect of sodium fluoride (NaF, CAS 7681-49-4) administration on phosphate metabolism and its impact on bone. Experiments were carried out in female fasted 50-day-old rats. Unless otherwise stated, NaF dose was 40 micromol NaF/day . 100 g bw, administered by gastric tube. Four groups of 4 rats each were given the following daily NaF doses: Group A: 0, B: 20, C: 40 and D: 60 micromol NaF/day x 100 g bw. After 30 days rats were killed saving their femora and plasma. Bone phosphorous contents (BPC) and phosphatemia (mg/dl) were measured. BPC decreased significantly as a function of NaF dose. A: 93.3+/-14.1; B: 78.7+/-15.5; C: 61.1+/-14.7**; D: 59.6+/-8.6 **mg P/g dry bone (** significant difference to group A, p < 0.01). Phosphatemia (mg/dl) increased significantly with a peak at 90 min after NaF dose (basal: 5.34+/-0.06; 90 min: 8.15 +/-0.43, p < 0.001). Phosphaturia (microg/min) increased though differences were not significant (basal: 46.7+/-42.8; 4 h: 1275 +/-757, p > 0.05). In thyroparathyroidectomized rats, plasma phosphate increased continuously for at least 240 min. Renal plasmatic flow, glomerular filtration rate and renal blood flow were not affected by NaF treatment. In isolated perfused rat kidneys, urinary phosphate excretion remained unaffected after NaF administration. Phosphate concentration was measured in the plasma and erythrocytes of rats after one dose of NaF (n = 8). Phosphate content of erythrocyte was not affected by NaF, in spite of the concurrent increase in phosphatemia. It is concluded that the treatment with NaF causes a transitory increase in plasma phosphate levels. Neither renal hemodynamic factors nor the inhibitory effect on parathormone actions appear to be the causes of hyperphosphatemia. Efflux of phosphate from cells might not be the cause of the increase in phosphatemia. The loss of phosphorous from bone appears as the most probable determinant of hyperphosphatemia after fluoride administration.

Fluoride Exposure Induces Inhibition of Sodium-and Potassium-Activated Adenosine Triphosphatase (Na+, K+-ATPase) Enzyme Activity: Molecular Mechanisms and Implications for Public Health

“…As previously elucidated, RANKL stimulates Pi release. Consistent with the mechanisms elucidated above, several human and animal studies have shown that F − intake can enhance Pi levels [349,358,359,360,361,362,363,364,365,366,367]. As Pi has been found to inhibit NKA activity, this provides a further mechanistic pathway by which F − inhibits NKA activity.…”

Metallofullerene nanoparticles promote osteogenic differentiation of bone marrow stromal cells through BMP signaling pathway

“…Aer 60 d of normal feeding, the ovariectomized rats were randomized into three groups (n ¼ 5/ group): the control group were subjected to intraperitoneal injection of 0.2 ml d À1 saline solution, the prevention groups were subjected to intraperitoneal injection of [Gd@C 82 (OH) 22 ] n nanoparticles at 228 mg kg À1 d À1 , at which concentration [Gd@C 82 (OH) 22 ] n nanoparticles have highly efficient antitumor activity in vivo, 1 and 400 mmol kg À1 d À1 NaF was used as the positive control. 48 Aer injection for 1 month, the animals were scanned by micro-CT and the 3D anatomic parameter of the tibia area was obtained by 3D reconstruction. Aer the rats were sacriced, various tissues were examined by ICP-MS and additionally bone tissue was analyzed by H&E staining.…”

Controlled fluoride release for osteoporosis treatment using orally administered chitosan hydrogels

“…Di Loreto et al (Di Loreto et al, 2006) observed that animals treated with a sodium fluoride dose between 1.26 and 3.40 mg/ g of body weight showed an increase in plasma phosphate levels after an hour of the administration. Chronically fluoride treated animals showed a decrease in bone phosphorus which is related to the increase in phosphatemia.…”