Role of Na(+)-K(+)-ATPase in lipopolysaccharide-induced cardiomyocyte hypertrophy in rats / 南方医科大学学报

ABSTRACT

<p><b>OBJECTIVE</b>To explore the possible mechanism of lipopolysaccharide (LPS)-induced cardiomyocyte hypertrophy in rats.</p><p><b>METHODS</b>Neonatal rat cardiomyocytes cultured in vitro were stimulated with 100 µg/L LPS for 1, 4 or 8 h and scanned by atomic force microscopy (AFM) for measurement of the two-dimensional area, three-dimensional surface area and volume of each cell. The total proteins and Na(+)-K(+)-ATPase activity in the cardiomyocytes were determined. The same measurements were also carried out in neonatal rat cardiomyocyte cultures stimulated by 0.5 µmol/L ouabain for 8 h and the total protein levels were measured.</p><p><b>RESULTS</b>Following a 8-hour stimulation with LPS, the two-dimensional area, three-dimensional surface area and volume of the single cardiomyocyte became enlarged and the total cellular proteins increased significantly as compared with those in the normal control cells (P < 0.05). LPS treatment for 4 and 8 h resulted in significantly decreased activity of Na(+)-K(+)-ATPase in the cardiomyocytes (P < 0.05). In the cells treated with ouabain for 8 h, the two-dimensional area, three-dimensional surface area, volume of the single cardiomyocyte and the total cellular proteins increased significantly in comparison with the normal control group (P < 0.05).</p><p><b>CONCLUSION</b>LPS can result in cardiomyocyte hypertrophy in rats possibly in relation to lowered Na(+)-K(+)-ATPase activity in the cardiomyocytes after LPS exposure.</p>