Influence of Dietary Magnesium on Cardiac and Renal Lesions of Young Rats Fed an Atherogenic Diet

Abstract

PLATES 93 TO 95(Received for publication, May 20, 1957) Evidence has been presented that the feeding of an atherogenic diet to weanling male rats increased the requirement for magnesium and that the atherosclerosis produced was made less severe or was delayed by the administration of large amounts of dietary magnesium (1).The present communication describes the morphology of the renal lesions found in rats fed the atherogenic diet (1). These lesions are consistent with magnesium deficiency despite the fact that the diets contained magnesium in excess of the amount for normal diets. The lesions of the heart, the aorta, and the liver are also described.Magnesium deficiency in animals, especially in rats, has been the subject of investigation since before 1932 (2-10). The histologic emphasis has been upon the renal lesions: these included calcific cast deposition in the corticomedullary zone extending into the pyramids and cortex, and renal epithelial degeneration and regeneration. Tubular dilation and finally hydronephrosis developed. Myocardial degeneration with fibrosis has been described (9) through lesions of atherosclerosis were not mentioned. The lesions of magnesium deficiency in calves included calcification of the yellow elastic fibers of the aorta and calcification in a few hearts (10).The possibility that metals may be implicated in atherosclerosis has aroused only limited interest and research activity. The concentrations of calcium and magnesium were found to be increased in atheromatous rabbit aortas (11) and with progressing age and atherosclerosis were also increased in the human aorta (12, 13). Dietary vanadium reduced the aortic cholesterol of cholesterol-fed rabbits, and vanadium

Nephrocalcinosis in Adolescent Sprague-Dawley Rats Fed Casein and Different Salt Mixtures

“…Rats feeding on the very iodine-rich AOAC mixture containing lower amounts of magnesium, zinc and fluorine developed a more pronounced nephrocalcinosis than those on the basal diet containing minerals according to Müller [9], Magnesium deprivation is known to promote the development of nephrocalcinosis in the rat [3] but it is doubtful if the level of magnesium obtained with the AOAC salt (29 mg%) is low enough to explain the higher frequency of calcification in this group. However, pronounced renal calcification has been observed in male rats fed an atherogenic diet containing 10% protein, 1% cholesterol, 0.3% cholic acid, 20% fat and 24 mg% magnesium [3], although only a slight reduction in the nephrocalcinosis was brought about by increasing the dietary magnesium content to 48 mg%, i.e. the same level of magnesium as in diets supplemented according to M uller [9].…”

“…Cousins and Geary [1] concluded that both estrogens and a dietary factor were implicated in the etiology of this condition. Several authors have demonstrated a lower incidence of renal calculi in rats fed diets containing additional casein [3][4][5]. Also, addition of gluten as well as supple mentation with methionine, cystine, glutamic acid and ammonium sulfate was effective in reducing the nephrocalcinosis [5], This was interpreted as an effect of acidification of the tubular fluid leading to an increased solubility of calcium phosphate [5].…”

Arteriosclerosis in Man, Other Mammals and Birds*

“…After testing a number of minerals often present in hard water, Neal & Neal (1962) reported that the addition of 3 yo magnesium sulphate to the drinking water of the cholesterol-fed rabbit prevents the development of gross plasma turbidity and atheroma. Conversely, magnesium deficiency in the cholesterol-fed rat and monkey (Cebus futuellu) leads to increased serum cholesterol and accentuated lipid deposition in arteries (Gottlieb, Broitman, Vitale & Zamcheck, 1959;Hellerstein et al, 1957; Vitale, Velez, Guzman & Correa, 1963). Excess dietary magnesium lactate, however, has neither hypocholesterolaemic nor anti-atherogenic actions in the cholesterol-fed rabbit (Adams, Bayliss, Ibrahim & Roper, 1964).…”

Experimentelle Aortalipoidose und renale Hypertonie der Ratte: Die Bedeutung der Schilddrüsen- und Gonadenfunktion.

“…6 (1966) erzeugender Diäten verstärkt (34,37). Umgekehrt wird durch Thyroxinapplikation normaler oder bereits erhöhter Blutdruck gesteigert (4), die experimentell erzeugte Aortalipoidose aber ver ringert (5,16).…”