Abnormal intracellular Ca
2+ homeostasis in the myocardium has been suggested as the cause of cardiac hypertrophy, and this process can be prevented by
the HMG-CoA reductase inhibitors, statins. In the present study, the effect of atorvastatin on left ventricular hypertrophy
was investigated, and then whether the underlying mechanism was related to a defect in intracellular Ca
2+ homeostasis explored. Twelve spontaneously hypertensive rats (SHR), at 8 weeks old, were used in this study, and received
either distilled water or atorvastatin for ten weeks, with age-matched normotensive Wistar-Kyoto rats (WKY) used as controls.
RT-PCR and western blotting were used to detect the mRNA and protein expressions of phospholamban (PLB) and sarcoplasmic reticulum
Ca
2+-ATPase (SERCA2a), respectively, and a colorimetric method used to examine the SERCA2a activity. Additionally, cardiac hypertrophic
indices, such as the cardiosomatic ratio, left ventricular weight to body weight (LVW/BW) ratio and cardiomyocytes transverse
diameter (TDM), together with the systolic blood pressure (SBP) and serum lipids levels were also examined. After ten weeks,
significant decreases were observed in both the mRNA and protein expression levels of SERCA2a, as well as its activity, in
the hypertrophied hearts of the SHR. The administration of atorvastatin to the same strains of rats effectively inhibited
these decreases, and the above cardiac hypertrophie indices, as well as the SBP and serum lipids levels were significantly
decreased. However, no significant changes in the expressions of PLB were observed in WKY, SHR and atorvastatin-treated SHR.
These findings demonstrated that through regulation of the PLB and SERCA2a levels in the hearts of SHR, atorvastatin can prevent
the cardiac hypertrophy caused due to pressure overload, which provides a relatively new insight into the mechanism of atorvastatin
in the prevention of cardiac hypertrophy.
Key words Atorvastatin - Phospholamban - Sarcoplasmic reticulum Ca2+-ATPase - Spontaneously hypertensive rat
Contributed equally as first author.