Effects of high-sodium diet on lithogenesis in a rat experimental model of calcium oxalate stones

Abstract

Background: This study aimed to investigate the effects of a high-and low-sodium diets on lithogenesis in a rat experimental model of calcium oxalate stones.Methods: Twenty male Wistar rats were randomly divided into four groups; group A: 4% NaCl+1% ethylene glycol (EG); group B: 8% NaCl+1% EG; group C: 8% NaCl+normal drinking-water; group D: 1% EG +normal diet. All rats were sacrificed 4 weeks later, and blood samples were collected from the heart.The kidneys were collected for Von Kossa staining to evaluate the formation of calcium-containing crystals.The last 24-h urine samples were also gathered for metabolic analysis.Results: Von Kossa staining demonstrated that the rats in both group A and group B had significantly more renal calcium crystals than those in group D. However, 24-h urinary volume increased significantly (142.26±20.91 mL) in group B compared with group A (100.52±28.23 mL), group C (107.36±14.24 mL), group D (40.79±8.71 mL) (P=0.004, 0.012, and 0.000 respectively). Level of urine sodium (Na), potassium (K), chlorine (Cl), and calcium (Ca), urea nitrogen were significantly higher in group B compared with group D. The urine phosphorus, oxalate, and creatinine levels; urine specific gravity; and urine PH were similar between group B and group D. The level of serum sodium was higher in group B (151.26±4.06 mmol/L) compared with group D (145.56±1.12 mmol/L) (P=0.002).Conclusions: A high sodium intake might increase the risk of lithogenesis in susceptible individuals (given by EG) or in individuals with water restriction.

Kidney Stone Prevention

“…High dietary sodium ingestion is accompanied by increased urinary calcium excretion [ 78 , 79 ] and CaOx crystal deposition in the kidney [ 80 , 81 ]. In pediatric patients, higher dietary sodium intake is also associated with calcium urolithiasis [ 82 ].…”

Metabolic changes in kidney stone disease

“…A high or low sodium concentration is a regulator of metabolic changes in patients with kidney stones. Sakhaee et al found that high sodium intake increased calcium excretion and urinary pH and decreased citric acid excretion (144,145). In addition, high sodium intake may reduce calcium reabsorption by the renal tubules, resulting in increased urinary calcium and stone formation (146).…”