Changes in the Cardiotoxic Effects of Lead Intoxication in Rats Induced by Muscular Exercise

Abstract

Exposure to lead is associated with an increased risk of cardiovascular diseases. Outbred white male rats were injected with lead acetate intraperitoneally three times a week and/or were forced to run at a speed of 25 m/min for 10 min 5 days a week. We performed noninvasive recording of arterial pressure, electrocardiogram and breathing parameters, and assessed some biochemical characteristics. Electrophoresis in polyacrylamide gel was used to determine the ratio of myosin heavy chains. An in vitro motility assay was employed to measure the sliding velocity of regulated thin filaments on myosin. Isolated multicellular preparations of the right ventricle myocardium were used to study contractility in isometric and physiological modes of contraction. Exercise under lead intoxication normalized the level of calcium and activity of the angiotensin-converting enzyme in the blood serum, normalized the isoelectric line voltage and T-wave amplitude on the electrocardiogram, increased the level of creatine kinase-MB and reduced the inspiratory rate. Additionally, the maximum sliding velocity and the myosin heavy chain ratio were partly normalized. The effect of exercise under lead intoxication on myocardial contractility was found to be variable. In toto, muscular loading was found to attenuate the effects of lead intoxication, as judged by the indicators of the cardiovascular system.

Non-Uniform Bioaccumulation of Lead and Arsenic in Two Remote Regions of the Human Heart’s Left Ventricle: A Post-Mortem Study

“…Klinova et al conducted an in vivo study to examine the cardiotoxic effect of Pb acetate. They administered a dose of 11 mg/kg body weight intraperitoneally over a 6-week period, three times a week, and discovered a significant reduction in the maximal velocity of reconstituted thin filament sliding over rat myosin under lead intoxication [ 31 ]. Gerzan et al exposed male rats to intraperitoneal doses of 12.5 mg of Pb per kg body mass and 6.01 mg of Pb per kg body mass over a five-week period.…”

The Role of Trace Elements in Cardiovascular Diseases

“…Pb, whose increased concentration in the left ventricle was noted by Ćirović et al [ 150 ], was identified as severely cardiotoxic in an animal study [ 151 ]. In detail, Klinova et al, observed higher levels of angiotensin-converting enzyme (ACE) and an amplified T-wave amplitude during an electrocardiograph examination.…”

“…In detail, Klinova et al, observed higher levels of angiotensin-converting enzyme (ACE) and an amplified T-wave amplitude during an electrocardiograph examination. In addition, the cardiomyocyte thickness of the lead-exposed group (5.38 ± 0.12 μm) was found to be higher than that of the control group (4.74 ± 0.08 μm); although this difference was relatively small, it was still statistically significant ( p < 0.01) [ 151 ]. Moreover, they recorded a reduction in the maximal velocity of thin filament slide over myosin, leading to a reduced contraction of the cardiomyocytes.…”

Accumulation of metal(loid)s in myocardial tissue and the mechanisms underlying their cardiotoxic effects

“…Knowledge on the cellular mechanisms underlying heavy metal-induced cardiotoxicity is primarily documented through in vivo experiments (22,23) and in vitro studies (10,24). Gerzan et al exposed male rats to lead acetate three times a week over a span of 35 days, demonstrating that lead impaired the mechanical characteristics of myosin in both the atria and ventricles (23).…”