Bexarotene enhances heart structure and function in diabetic rats by inhibiting ventricular remodeling and cardiomyocyte apoptosis

Purpose: To investigate the influence of bexarotene (Bex) on cardiac structure and function in streptozotocin (STZ)-induced diabetes mellitus (DM) rats, and the mechanism of action involved. Methods: Four groups of Sprague Dawley rats (n = 40) were used: normal control, DM, DM+Bex (10 mg/kg/day), and DM+Bex (20 mg/kg/day) (n = 10). The DM rat model was established by intraperitoneal injection of STZ. Cardiac structure and function of rats were determined and compared. Whole heart and left ventricle were weighed. The protein expressions of Bcl2 and Bax in rat myocardial tissue were determined using Western blotting. Results: Compared to control group, there was significant reduction in the levels of IVSd (inlet ventricular septal defect) and LVPWd (left ventricle posterior wall in diastole) in DM group, but significant increase in these parameters in DM + Bex (20 mg/kg/day) group, relative to DM-treated rats (p < 0.05). Moreover, there were higher expression levels of Bcl2 and Bax in DM group, when compared with normal control, but Bcl2/Bax ratio was significantly lower (p < 0.05). Furthermore, Bcl2 and Bax levels in DM + Bex (20 mg/kg/day) group were significantly lower than those in DM group, while Bcl2/Bax ratio increased significantly (p < 0.05). Conclusion: Bexarotene improves the cardiac structure of DM rats by lowering blood glucose, and by inhibiting ventricular remodeling and cardiomyocyte apoptosis. These findings may be beneficial in the development of new anti-DM drugs.