Key result
Chronic trace lindane exposure shortens left ventricular action potential duration and impairs myocardial integrity in rats.
Why the study?
The silent effects of chronic exposure to trace concentrations of lindane on heart muscle morphology and electrical activity were not well characterized.
Does chronic exposure to trace concentrations of lindane alter the electrical activity and morphology of the heart in adult rat offspring?
Does chronic exposure to trace concentrations of lindane alter the electrical activity and morphology of the heart in adult rat offspring?
Chronic exposure to trace concentrations of lindane alters tissue integrity and shortens action potential duration in the left ventricle of rat offspring, indicating silent cardiotoxic effects.
May indicate developmental cardiac risk from trace lindane; leaves open human relevance and need for prospective studies.
The heart of adult rat offspring, born to mothers treated with trace concentrations of lindane (0.5 to 2 ppb) through a beverage and to mothers chronically treated with lindane (CL-T) with the same trace concentration, also through a beverage, during lactation and growth has a round shape and accumulates lindane. The left ventricle (LV) presents a hypertrophied area, atrophied papillary muscles, and unorganized collagen bundles and layers. These observations led us to study the electrical activity of their left ventricle papillary muscles (LVPM) by recording action potential using intracellular microelectrodes. CL-T shortened LVPM action potential duration (APD): 1 ppb shortened the plateau; 2 ppb shortened the plateau and the slow repolarizing phase. In CL-T (2 ppb) and untreated groups, low temperature (22 degrees C) decreased the resting potential and prolonged APD. TEA (tetraethylammonium; 1-2 mmol/L) partially lengthened CL-T (2 ppb lindane) APD. Quinidine (0.2 mmol/L) and E-4031 (10 nmol/L) prolonged CL-T APD, suggesting that the rapid delayed outward K+ current (IKr) was increased. Our results indicate the silent effects of chronic exposure to trace concentrations of lindane on the morphological and electrical activity of heart muscle. They demonstrate that chronic lindane treatment of female rats alters the tissue integrity and electrical activity in the LV of their offspring.
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Sauviat et al. (2005) studied this question. Lindane (γ-hexachlorocyclohexane) vs. Untreated groups was evaluated on Left ventricle papillary muscle action potential duration and morphology. Chronic exposure to trace concentrations of lindane (1-2 ppb) shortened left ventricle papillary muscle action potential duration and altered tissue integrity in adult rat offspring.
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