OBJECTIVETo assess the impact of transfection with recombinant adenovirus vector-mediated Klotho gene on myocardial remodeling in a rat model of heart failure (HF) by intraperitoneal injection of isoproterenol.

METHODSRats were divided into 5 groups by table of exponential random numbers: normal control group, HF group, saline-control HF group, recombinant adenovirus vector transfection group (Ad.EGFP group, 2 × 10¹⁰ pfu, 0.5 ml/rat), pDC316-CMV-EGFP-rKlotho transfection group (Ad.Klotho group, n=5 each). Left ventricular ejection fraction (LVEF) was obtained by echocardiography, hemodynamic parameters obtained by multi-channel physiological recorder, myocardial tissue underwent pathohistological examination. Additionally, the green fluorescin expression was observed on frozen heart section. Myocardial fibrosis correlated gene expression including Klotho gene, collagen I and III was detected by real time-PCR. Moreover, plasma levels of B-type natriuretic peptide (BNP) were measured with ELISA.

RESULTSCompared to saline control HF group, LVEF, LVSP and ±dp/dtmax were significantly increased, myocardial fibrosis and myocardial remodeling were significantly attenuated in the Ad. Klotho group and there was green fluorescin distribution in myocardial tissues of Ad. Klotho group. Klotho expression was down-regulated and collagen I and III expression was upregulated in HF rats compared to normal control group (all P<0.05) and these changes could be significantly reversed in Ad. Klotho group (all P<0.05). Plasma BNP level was also significantly lower in Ad. Klotho group than in HF group (P<0.05).

CONCLUSIONSKlotho gene transfection could improve cardiac function and attenuate cardiac remodeling and reducing myocardial fibrosis.