Dietary Monosodium Glutamate Does Not Affect the Electrocardiographic Profiles of Diabetic and Nondiabetic Wistar Rats

Abstract

Background and Aims: Some studies have recently indicated that dietary monosodium glutamate (MSG) is linked to obesity and the development of diabetes. Both diseases induce cardiovascular changes, such as increases in blood pressure and arrhythmias, including ventricular fibrillation, which may result in sudden death. Here, we aimed to investigate the effects of oral MSG administration on the electrical conduction and histological dysfunctions of the heart in control and diabetic Wistar rats. Methods and Results: Twenty-one-day-old Wistar rats were fed diets containing 0.0%, 1.0%, 2.5% or 5.0% MSG for 70 days. After this period, diabetes was induced with streptozotocin (STZ; 50 mg/kg bw) in half the rats and after an additional 21 days period; the electrocardiographic parameters and heart histology were evaluated. Diabetic rats demonstrated a reduction in heart rate as well as an enlargement of the QRS complex and QT and QTc intervals. Nevertheless, those changes are typical of STZ-induced diabetes, mainly because of electrolyte disturbances. The presence of MSG in the diet did not change the parameters evaluated between the group that received MSG and the group that did not receive MSG. Moreover, no histological alterations in the heart were observed due to MSG ingestion. Conclusion: Based on this evidence, diets containing MSG did not interfere with cardiovascular changes due to diabetes; there were no differences in the electrocardiographic and histological characteristics of the hearts of rats treated with MSG.