Inhibitory effect of fluoride on renal stone formation in rats

Area of Science:

• Nephrology
• Toxicology
• Biochemistry

Background:

• Kidney stones, particularly calcium oxalate stones, represent a significant health burden.
• Ethylene glycol (EG) is commonly used to induce experimental urolithiasis in animal models.
• The role of fluoride in modulating stone formation pathways requires further elucidation.

Purpose of the Study:

• To investigate the effect of fluorine, specifically sodium fluoride (NaF), on ethylene glycol (EG)-induced kidney stone formation in rats.
• To assess the impact of NaF on urinary oxalate excretion and calcium deposition in the kidneys.

Main Methods:

• Rats were administered EG, NaF, or a combination of EG and NaF in their drinking water for four weeks.
• Kidney stone formation was evaluated macroscopically.
• An isotope-tracing method using 45Ca was employed to quantify calcium deposition in the kidneys.
• Urinary oxalate levels were measured.

Main Results:

• The group receiving both EG and NaF exhibited a significantly lower incidence of gross urinary stones compared to the EG-only group.
• Kidney 45Ca activity was markedly reduced in the EG+NaF group relative to the EG group.
• While both EG and EG+NaF groups showed increased urinary oxalate excretion, the EG+NaF group had significantly lower levels than the EG group.
• NaF administration alone resulted in lower urinary oxalate excretion compared to the control group.

Conclusions:

• Sodium fluoride (NaF) demonstrates an inhibitory effect on ethylene glycol-induced renal stone formation in rats.
• NaF appears to exert its protective effect by reducing oxalate synthesis and subsequent urinary oxalate excretion.
• These findings suggest a potential clinical application for NaF in the prevention of oxalate kidney stones.