[Role of Na(+)-K(+)-ATPase in lipopolysaccharide-induced cardiomyocyte hypertrophy in rats].
OBJECTIVE
To explore the possible mechanism of lipopolysaccharide (LPS)-induced cardiomyocyte hypertrophy in rats.


METHODS
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.


RESULTS
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).


CONCLUSIONS
LPS can result in cardiomyocyte hypertrophy in rats possibly in relation to lowered Na(+)-K(+)-ATPase activity in the cardiomyocytes after LPS exposure.
Wang
Li-qun
LQ
Center of Medical Experiment Teaching, Southern Medical University, Guangzhou 510515, China. yy000213@163.com
Chen
Tang-ting
TT
Cai
Ying-qian
YQ
Xue
Xiang
X
Zhou
Xiang
X
Jin
Chun-hua
CH
D000818:Animals; D000831:Animals, Newborn; D049108:Cell Enlargement / Q000187:drug effects*; D002478:Cells, Cultured; D006984:Hypertrophy / Q000139:chemically induced; D008070:Lipopolysaccharides; D032383:Myocytes, Cardiac / Q000201:enzymology / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D008070:Lipopolysaccharides; D000254:Sodium-Potassium-Exchanging ATPase