STUDIES OF EXPERIMENTAL CALCIUM OXALATE STONE 1. The Affection of Calcium and Magnesium of Renal Deposition of Calcium Oxalate Induced by Ethylene Glycol Administration

• Published in: The Japanese Journal of Urology Vol. 76; no. 6; pp. 831 - 842
• Main Authors: Ebisuno, Shoichi, Morimoto, Shigeyoshi, Fukatani, Toshiro, Miyazaki, Yoshihisa, Yasukawa, Shu, Sawada, Yoshihisa, Ohkawa, Tadashi
• Format: Journal Article
• Language: Japanese
• Published: THE JAPANESE UROLOGICAL ASSOCIATION 20.06.1985
• ISSN: 0021-5287; 1884-7110
• DOI: 10.5980/jpnjurol1928.76.6_831

Oral administration of ethylene glycol (EG) to rats, and resultant renal depositions of microcrystal of calcium oxalate were studied in terms of various urinary metabolites following intakes of dietary levels of calcium and magnesium. We employed an experimental hyperoxaluria protocol involving the administration of 1% EG for initial 3 days and 0.1% EG for the following 2 weeks by drinking water ad libitum. The manner of administration of EG was based on the “trigger theory” by Vermeulen and associates. Renal tubular deposits of calcium oxalate were estimated using a histological grading (Grade 0-Grade 3) and calcium contents of the whole renal tissue. There were direct correlations between dietary calcium and magnesium and their excretions in urine. The microcrystals of calcium oxalate in renal tubulus were hardly seen in rats of the group receiving low-Ca diet, although they remained hyperoxaluria like the groups of high-Ca middle-Ca diet. With increasing calcium intakes there was a marked increase in the amount of the deposits of calcium oxalate. In addition, there was a significant increase in the calcium contents of renal tissue. When the rats fed middle-Ca diet, the depositions of calcium oxalate were reduced markedly in the group of 0.1% EG maintenance for 2 weeks. It is suggested that resultant microcrystals may disappear or can not develop without a maintenance of severe hyperoxaluria or hypercalciuria. Apatite crystal was observed only in the group receiving low-Mg diet, and both crystals, calcium oxalate and apatite, were seen in the same group with EG. Although it was showed that magnesium deficiency accelerated renal tubular calcium oxalate deposition in rats on this hyperoxaluric protocol, the protection of calcium oxalate deposition was not achieved with excessive dietary magnesium. A higher correlation was found to exist between intratubular calcium oxalate depostion and renal calcium content in rats administered EG except the group of magnesium depletion. It is suggested that a determination of renal calcium content in experimental stone study is useful for estimation of the severity of crystal formation or the efficacies of some anticalculous agents.