RESUMEN
PURPOSE: Water intake is important for preventing kidney stones. Small molecules water is a more active restructured water under magnetic field. Here, we studied the relation between small molecules water and crystal formation in the rat kidney. MATERIALS: The small molecules water was prepared by a water machine providing a 0.8-T magnetic field. Calcium oxalate crystals were induced by 0.75% EG (ethylene glycol) in male Sprague-Dawley rats by drinking small molecules water and plain water for up to 6 weeks, respectively. Urinary ions were assayed. Osteopontin mRNA expression and urinary LDH were detected. Crystals were observed using a light microscope and a polarizing microscope. RESULTS: A significantly reduced urinary calcium and phosphorus excretion occurred in the 2nd and the 4th week after treatment of small molecules water. Crystals were initially detected in 40% of the experimental rats in the small molecules water group at the 6th week, later than the control group in which crystals were detected in 60% of rats at the 4th week. After 6 weeks of treatment, crystals were observed to form in renal cortex, medulla and papilla in the control group, whereas only to form in renal medulla and papilla in the small molecules water group. OPN mRNA expression significantly increased earlier in the 2nd week after treatment of the small molecules water compared to the control (P = 0.016). CONCLUSIONS: Small molecules water may retard crystal formation, reduce urinary calcium and phosphorus excretion and promote earlier OPN mRNA expression in the rat kidney.