Atorvastatin Attenuates Myocardial Hypertrophy in Spontaneously Hypertensive Rats via the C/EBPβ/PGC-1α/UCP3 Pathway.

BACKGROUND/AIMS: Many clinical and experimental studies have shown that treatment with statins could prevent myocardial hypertrophy and remodeling induced by hypertension and myocardial infarction. But the molecular mechanism was not clear. We aimed to investigate the beneficial effects of atorvastatin on hypertension-induced myocardial hypertrophy and remodeling in spontaneously hypertensive rats (SHR) with the hope of revealing other potential mechanisms or target pathways to interpret the pleiotropic effects of atorvastatin on myocardial hypertrophy.

METHODS: The male and age-matched animals were randomly divided into three groups: control group (8 WKY), SHR (8 rats) and intervention group (8 SHR). The SHR in intervention group were administered by oral gavage with atorvastatin (suspension in distilled water, 10 mg/Kg once a day) for 6 weeks, and the other two groups were administered by gavage with equal quantity distilled water. Blood pressure of rats was measured every weeks using a standard tail cuff sphygmomanometer. Left ventricular (LV) dimensions were measured from short-axis views of LV under M-mode tracings using Doppler echocardiograph. Cardiomyocyte apoptosis was assessed by the TUNEL assay. The protein expression of C/EBPβ, PGC-1α and UCP3 were detected by immunohistochemistry or Western blot analysis.

RESULTS: At the age of 16 weeks, the mean arterial pressure of rats in three groups were 103.6±6.1, 151.8±12.5 and 159.1±6.2 mmHg respectively, and there wasn't statistically significant difference between the SHR and intervention groups. Staining with Masson's trichrome demonstrated that the increased interstitial fibrosis of LV and ventricular remodeling in the SHR group were attenuated by atorvastatin treatment. Echocardiography examination exhibited that SHR with atorvastatin treatment showed an LV wall thickness that was obviously lower than that of water-treated SHR. In hypertrophic myocardium, accompanied by increasing C/EBPβ expression and the percentage of TUNEL-positive cells, the expression of Bcl-2/Bax ratio, PGC-1α and UCP3 were reduced, all of which could be abrogated by treatment with atorvastatin for 6 weeks.

CONCLUSION: This study further confirmed that atorvastatin could attenuate myocardial hypertrophy and remodeling in SHR by inhibiting apoptosis and reversing changes in mitochondrial metabolism. The C/EBPβ/PGC-1α/UCP3 signaling pathway might also be important for elucidating the beneficial pleiotropic effects of atorvastatin on myocardial hypertrophy.