GALLIUM CHLORIDE EFFECTS ON NEONATAL RAT-HEART CELLS IN CULTURE, IN STANDARD AND OXIDATIVE CONDITIONS

The effects of gallium chloride (GaCl3) at 7.17, 28.68 and 114.7 mu m (0.5, 2 and 8 mg/l of Ga3+) were checked in cardiac cells derived from 2-4 day-old newborn rats, cultured for 72 h in Eagle's minimum essent ial medium (MEM), enriched with 10% foetal calf serum (v/v) and 2 mM o f glutamine at 37 degrees C, with 95% air plus 5% CO2. After 3 hours o f standard culture conditions (MEM with glucose 5 mM), Ga treatment in duced an increase of glycogen stores without any influence on ATP, ADP , and AMP concentrations. A slight and transient decrease in the beat rate was noted after 15 min of exposure to GaCl3 at all concentrations , whereas there was no difference in the beat rate nor in the cell con traction amplitude after 3 hours of exposure. After 1.5 h in condition s of oxidation (Tyrode solution without glucose, FeCl2 20 mu M, ascorb ic acid 0.2 mM), GaCl3 at 8 mg/l decreased the malondialdehyde (MDA) p roduction as assessed by the decrease of intracellular concentrations and the decrease of its release in the supernatant. The decreased MDA production following oxidative stress, the increase in glycogen stores in normal oxygen concentrations, as well as the maintenance of ATP co ncentrations and the lack of any chronotropic effect induced by GaCl3 suggests a protective rather than a deleterious cardiac effect.