Bisoprolol and linagliptin ameliorated electrical and mechanical isometric myocardial contractions in doxorubicin-induced cardiomyopathy in rats

Doxorubicin is an anthracycline chemotherapeutic agent that causes cardiomyopathy as a side effect. Here, we aimed to investigate the effects of linagliptin and bisoprolol on the management of doxorubicin-induced cardiomyopathy in rats. Wistar rats were divided into six groups (n = 8). Group I received saline for 4 weeks; group II received 1 mg/kg bisoprolol for 8 weeks; group III received 3 mg/kg linagliptin for 8 weeks; group IV received 1.25 mg/kg doxorubicin for 4 weeks for the induction of cardiomyopathy; group V received 1.25 mg/kg doxorubicin for 4 weeks plus 1 mg/kg bisoprolol for 8 weeks; and group VI received 1.25 mg/kg doxorubicin for 4 weeks plus 3 mg/kg linagliptin for 8 weeks. Electrocardiography and isometric mechanography were conducted to measure ventricular contractile responses. Myocardial tissue and serum samples were analyzed for oxidative and cardiotoxic markers by ELISA. Electrocardiography revealed that QRS, QT and Tp intervals were longer in group IV than group I. Doxorubicin caused a significant decrease in ventricular contraction, which was significantly prevented by bisoprolol. Doxorubicin resulted in myocardial fiber disorganization and disruption, but bisoprolol or linagliptin improved this myocardial damage. Glutathione peroxidase was significantly decreased in groups IV and V. Bisoprolol or linagliptin treatment attenuated the significant doxorubicin-mediated increase in malondialdehyde. Doxorubicin and linagliptin provided significant elevations in CK-MB activity and troponin-I levels. Doxorubicin resulted in pronounced oxidative stress. The beneficial effects of bisoprolol and linagliptin on myocardial functional, histopathological and biochemical changes could be related to the attenuation of oxidative load.