Epidemiological studies showed that
hypercholesterolemia was associated with a higher left ventricular mass. Myocardial
ATP-sensitive
potassium (K(
ATP)) channels have been implicated in the development of
cardiac hypertrophy. We investigated the effect of
pravastatin on
hypercholesterolemia-induced ventricular
hypertrophy and whether the attenuated hypertrophic effect was via activation of myocardial K(
ATP) channels. In this study, we evaluated the hemodynamic, biochemical, and morphological responses to
pravastatin in
cholesterol-fed (1%) rabbits. Male New Zealand White rabbits were randomized to either vehicle,
nicorandil (an agonist of K(
ATP) channels),
pravastatin,
glibenclamide (an antagonist of K(
ATP) channels), or a combination of
nicorandil and
glibenclamide or
pravastatin and
glibenclamide for 8 weeks. The left ventricular weight and left ventricular myocyte sizes increased 8 weeks after
cholesterol-feeding in comparison to that in normocholesterolemic rabbits.
Pravastatin administration significantly decreased the left ventricular weight by 12% and cardiomyocyte cell areas by 30%. Hyperlipidemic rabbits in the
nicorandil- and
pravastatin-treated groups significantly attenuated cardiomyocyte
hypertrophy, as compared with the vehicle-treated group (3162 +/- 277 microm(2), 3372 +/- 228 microm(2) versus 4388 +/- 163 microm(2) in the vehicle group, both P < 0.0001, respectively).
Nicorandil-induced effects were abolished by administering
glibenclamide. Similarly,
pravastatin-induced beneficial effects were reversed by the addition of
glibenclamide, implicating K(
ATP) channels as the relevant target. The results of the present study suggest a pathogenetic role of K(
ATP) channels in
hypercholesterolemia-induced ventricular
hypertrophy. The antihypertropic effects of
pravastatin may be related to activation of K(
ATP) channels, and result in an amelioration of cardiomyocyte
hypertrophy development by an atherogenic diet.