Ranolazine protects against diabetic cardiomyopathy by activating the NOTCH1/NRG1 pathway

Aims Diabetic cardiomyopathy (DCM) is a common diabetes complication that can cause arrhythmia, heart failure, and even sudden death. Ranolazine is an antianginal agent used to treat chronic stable angina and has been demonstrated as an effective treatment for many cardiovascular diseases. However, the mechanism by which ranolazine alleviates DCM is unclear, motivating this study investigating the effects of ranolazine in DCM. Materials and methods DCM rats were treated with one of three doses of ranolazine (10, 30, and 90 mg/kg/day) for 12 weeks. B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X protein (Bax), cysteinyl aspartate specific proteinase-3 (Caspase-3), Notch homolog 1 (NOTCH1), and Neuregulin 1 (NRG1) expression was assayed using western blot and qRT-PCR. Cardiac changes were assayed using echocardiography, CT, HE staining, and Masson's trichrome staining. TUNEL staining and flow cytometry were used to detect cell apoptosis. NOTCH1 inhibitor (DAPT) was used to explore the mechanism of ranolazine. Key findings Compared with the DCM group, the ranolazine groups had no obvious weight loss and significantly decreased blood glucose levels. Ranolazine prevented diabetes-caused cardiac injury. Ranolazine also decreased the number of apoptotic cells and altered the expression of apoptosis-related mRNAs and proteins. Ranolazine-induced NOTCH1 activated NRG1 and inhibited the downstream apoptosis-related pathway, while DAPT partially inhibited ranolazine-induced NOTCH1 and NRG1 expression. Significance To our knowledge, this study is the first to demonstrate that ranolazine protects against DCM-induced apoptosis by activating the NOTCH1/NRG1 signaling pathway. Moreover, our study identified new mechanisms involved in DCM.