The role of (pro)rennin receptor (PRR) in cardiomyocytes of a heart failure (HF) rat model was studied. Spontaneously hypertensive rats (SHR) with HF (SHR-HF) or not were identified by two-dimensional (2-D) ultrasound. Age-matched Wistar Kyoto normotensive (WKY) rats were used as controls. PRR short hair RNA (sh-RNA) was injected into the heart of SHR-HF. Simultaneously SHR and controls received the same shRNA injection into the heart. Scramble shRNA was injected into the heart as controls. The expression of PRR mRNA and protein in cardiomyocytes was detected by using real-time PCR and Western blotting respectively. The heart function was evaluated by 2-D ultrasound, including eject fraction (EF%), fractional shortening (FS%), left ventricle thickness (LV), and inter-ventricular septal thickness (IVS). The number of apoptotic cardiomyocytes was counted by using flow cytometry. The results showed that the mRNA and protein expression levels of PRR were significantly higher in cardiomyocytes of SHR-HF group than in those of SHR group or control group. The apoptosis of myocytes in SHR-HF group was increased as compared with SHR group or control group. After knock-down of PRR with shRNA in SHR-HF group, the apoptosis of myocytes was reduced, resulting in the improved heart function. It was suggested that down-regulation of PRR might protect the heart from development of HF in SHR-HF by inhibiting the apoptosis of cardiomyocytes.