Beneficial effects of dietary magnesium and potassium on cardiac and renalmorphologic features in cyclosporin A-induced damage in spontaneously hypertensive rats

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 spontane ously hypertensive rats (SHRs) on high-sodium diet. Methods. Eight-week-old SHRs were divided into 4 groups: (I) receiving a hi gh-sodium diet, (2) receiving a high-sodium, high-potassium diet, (3) recei ving a high-sodium, high-magnesium diet, and (4) receiving a high-sodium, h igh-potassium high-magnesium diet. The effects of cyclosporin A in SHRs on a relatively low-sodium diet and in normotensive Wistar-Kyoto rats were als o examined. Cardiac and renal morphologic condition was assessed, and tissu e damage was scored by Eight microscopy after 4 weeks of cyclosporin A trea tment. Results. In SHRs on a high-sodium diet, cyclosporin A caused luminal narrow ing 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 pota ssium alone was less effective. Cyclosporin A treatment caused only minor h istopathologic changes in SHRs receiving a low-sodium diet. Interestingly, the detrimental interaction between cyclosporin A and a high-sodium diet wa s also observed in normotensive Wistar-Kyoto rats. Conclusions. Dietary magnesium, especially in combination with potassium, p rotects against cyclosporin A-induced cardiac and renal damage.