Beneficial effects of dietary magnesium and potassium on cardiac and renal morphologic features in cyclosporin A–induced damage in spontaneously hypertensive rats

Abstract

Background: Cyclosporin A–induced hypertension is dependent on the level of dietary salt. We investigated whether dietary magnesium or potassium could protect against cyclosporin A–induced cardiac and renal damage in spontaneously hypertensive rats (SHRs) on high-sodium diet. Methods: Eight-week-old SHRs were divided into 4 groups: (1) receiving a high-sodium diet, (2) receiving a high-sodium, high-potassium diet, (3) receiving a high-sodium, high-magnesium diet, and (4) receiving a high-sodium, high-potassium, high-magnesium diet. The effects of cyclosporin A in SHRs on a relatively low-sodium diet and in normotensive Wistar-Kyoto rats were also examined. Cardiac and renal morphologic condition was assessed, and tissue damage was scored by light microscopy after 6 weeks of cyclosporin A treatment. Results: In SHRs on a high-sodium diet, cyclosporin A caused luminal narrowing of the coronary arteries, left ventricular scarring, and damage in the renal arterioli and glomeruli. Dietary magnesium supplementation alone and in combination with potassium protected against these changes, whereas potassium alone was less effective. Cyclosporin A treatment caused only minor histopathologic changes in SHRs receiving a low-sodium diet. Interestingly, the detrimental interaction between cyclosporin A and a high-sodium diet was also observed in normotensive Wistar-Kyoto rats. Conclusions: Dietary magnesium, especially in combination with potassium, protects against cyclosporin A–induced cardiac and renal damage. (Surgery 2000;128:67-75.)