[ effects of orally administrated magnesium on isolated aorta contractility in streptozotocin induced diabetic rats]

ABSTRACT

Some studies suggest that magnesium deficiency contributes to the cardiovascular complications associated with diabetes mellitus. Hence the present study investigated the effects of orally administrated magnesium on isolated aorta contractility in response to KCI and Phenylephrine [Phe]. Sixty male Wister rats [180-250 g] were divided into two diabetic and two control groups. One sub group of each received magnesium sulfate in their drinking water, while two other groups, had only tap water. After 8 weeks, thoracic aorta was isolated, cut into 2-3 mm rings and mounted in an organ bath. The tissue was then exposed to cumulative doses of KCI [10, 20, 40, 60 and 80mM] and Phe [10-9, 10-8, 10-7, 10-6, and 10-5M] and contractions were measured by an isometric transducer. During the mentioned time, fasting blood samples were drawn every 2 weeks to measure plasma glucose level. Vasoconstrictive responses to KCI and Phe were significantly higher in control groups, compared to diabetic groups [P<.05] and there were no significant differences between Mg-treated and non Mg-treated rats. Maximal contractions to KCI were 2.91 +/- 0.31, 2.79 +/- 0.18, 2.37 +/- 0.16 and 2.42 +/- 0.11 and the maximal responses to Phe were 3.25 +/- 0.17, 3.12 +/- 0.25, 2.57 +/- 0.33 and 2.73 +/- .21 in control, Mg-treated control, diabetes and Mg-treated diabetic groups, respectively. No significant difference was found in plasma glucose between Mg-treated groups and non mg-treated groups. Oral administration of magnesium for 8 weeks has no effect on isolated aorta contractility in diabetic rats