Objective  To investigate the protective effect of nicodil on cardiac function and left ventricular remodeling in ischemic heart failure rats and its related mechanism.

  Methods  Forty rats were randomly divided into blank control group (Con group), nicodil group (NIC group), normal saline group (NS group) and Sham operation group (Sham group), with 10 rats in each group, and different treatment methods were adopted. The differences of body weight, respiratory pattern, activity and hair color were recorded. Echocardiography was performed in all rats 8 weeks after operation. After the experiment, the anterior wall tissue of the left ventricle of rats was observed by HE staining and electron microscopy. The relative expression levels of p-Akt, Bcl-2 protein and Bax in myocardial tissue were detected.

  Results  Compared with Con group and Sham group, left ventricular ejection fraction (LVEF) and ratio of maximum velocity (E) to atrial contraction maximum ventricular filling velocity (A) (E/A) in NS group and NIC group were significantly decreased, and LVEF in NS group had the most decrease (P < 0.05). The left ventricular end-diastolicvolume (LVEDV) showed an opposite trend, with significant differences among the three groups, and the NS group had the highest LVEDV (P < 0.05). Left ventricular end-systolic volume (LVESV), left ventricular end-diastolic diameter (LVIDd) and left ventricular end-systolic diameter (LVIDs) in NS group were significantly higher than those in NIC group and Sham group (P < 0.05). In the Sham group, the myocardial cells were arranged regularly and the transverse lines were clear; in the NS group, the myocardial cells were disordered and irregular in shape, and obvious fibrous tissue proliferation was also observed. However, compared with NS group, these abnormalities in NIC group were significantly reduced and myocardial fiber structure tended to be normal. The ratio of left ventricular weight (LVW) to body weight (LVW/BW) and lung mass index (Lungw/Bw) in Sham group and NIC group were significantly lower than those in NS group (P < 0.05). Compared with Con group and Sham group, the relative expression levels of p-Akt protein, Bcl-2 protein and Bax protein in NS group were significantly increased (P < 0.05). The relative expression levels of p-Akt protein and Bcl-2 protein in NIC group were significantly higher than those in NS group, but the expression level of Bax protein was significantly decreased (P < 0.05).

  Conclusion  Nicorandil can protect rats with ischemic heart failure by improving cardiac function and left ventricular remodeling, which may be related to the inhibition of Bax protein expression.