Changes of Renal Calcium Content and CaOx Crystal Deposit after Unilateral Nephrectomy in Rats

Park, Myung Seung; Kim, Young Gon

Abstract

PURPOSE: The surgical removal of normal kidney elicits dramatic changes in the remaining kidney. Changes in urinary excretion of lithogenlc substances and urinary inhibitor may increase or decrease the stone-forming potential. The aim of this study was to determine if unilateral nephrectomy could enhance urinary calculi formation in animal model.
MATERIALS AND METHODS
Adult male rats were divided randomly into 3 groups. Group 1(n=5) were fed with pellet and tap water for 4 weeks without nephrectomy Group 2(n=5) were fed with the same pellet and 0.8% ethylene glycol plus 1% ammonium chloride in drinking water for 4 weeks without nephrectomy Group 3(n=5) were fed with the same pellet and the same lithogenic diet from 2 weeks after uninephrectomy for 4 weeks. Each right kidney was harvested after 4 weeks feeding. One half of the each kidney were fixed for H & E stain to examine crystal deposits. The remaining half of the kidneys were treated with 12N KOH and 6N HCI for the measurement of calcium content with atomic absorption spectrophotometer. About 3-5cc of blood was collected from the inferior vela cava for determinations of serum creatinine, calcium, magnesium and phosphorus & chloride. Urine was collected over a 24 hour interval before and after lithogenic diet, and urine volume, 24-hour urinary excretions of oxalate, citrate, uric acid, calcium, magnesium, phosphate, sodium, potassium, chloride, and creatinine were measured.
RESULTS
There was a significant difference between group 1(0.243 +/- 0.014mmo1/kg) and lithogenic diet groups(group 2 and group 3 in calcium content(p < 0.01)). But, there was no significant difference of calcium content between group 2(5.475 +/- 0.247mmo1/kg) and group 3(5.843 +/- 0.324mmol/kg)(p > 0.05). There were no calcium oxalate crystal deposit in the group 1, but there were about 2-5 crystal deposits with partially polarized light microscope( x 100) in group 2 and group 3, and there was no significant difference between group 2 and group 3. After taking lithogenic diet, the serum creatinine, serum magnesium, serum phosphors, urine pH & 24-hour urinary excretions of oxalate increased significantly in group 2 and group 3, whereas creatinine clearance & 24-hour urinary excretions of calcium, sodium, potassium, chloride, citrate decreased significantly in the same groups(p < 0.05). But, there were no significant difference of serum calcium, chloride, and 24-hour urinary excretions of magnesium, uric acid among three groups after 4 weeks feeding.
CONCLUSIONS
Unilateral nephrectomy would not increase stone forming potential.