ABSTRACT
Aim To investigate the protective effect of naringin ( NA) on diabetic cardiomyopathy by activating the large conduction Ca2+ activated K4 channels (Maxi K ).Methods SD rats were fed with high-fat diet combined with intraperitoneal injection of strepto- zotocin (STZ) to establish a diabetic rat model.Then the rats were randomly divided into model group ( DCM) , naringin group ( NA) and naringin + Maxi K-specific inhibitor group ( NA + PAX) , with 8 rats in each group.Hats in treatment group received administration for 12 weeks and blood glucose was monitored regularly during experiments.The changes of cardiac function, morphology and fibrosis were detected after the treatment.The changes of cx and (3 subunits of Maxi K in heart were detected.Results Cardiac ultrasound results showed that NA could partially restore the cardiac function of rats.However, the cardiac protec tive function of NA was significantly reduced in diabetic rats after Maxi K was specifically blocked.Fibrosis analysis showed that the expression of collagen and fi- bronectin in rats could be decreased after NA treatment, which could be partially reversed by PAX.Western blot results showed that the expression of Maxi K a and p-subunit decreased in DCM group, but there was no significant change after NA treatment.Conclusions NA has a cardioprotective effect on diabetic rats by promoting the opening of the Maxi K channel on the membrane surface rather than increasing its expression.
ABSTRACT
Objective: To investigate the effect of losartan on angiotensin II (Ang II) expression and myocardial remodeling in myocardial infarction (MI) rats’ model. Methods: A total of 32 SD male rats were divided into 4 groups, Sham operation group, MI group, MI with losartan 10mg/(kg·d) group and MI with losartan 20mg/(kg·d). n=8 in each group. MI model was established and the electrocardiogram changes before and after MI were recorded, hemodynamic indexes were detected at 4 weeks after MI, pathological changes of myocardial tissue were examined by HE staining. The myocardial mRNA and protein expressions of ACE2 and Ang II were detected by RT-PCR and Western Blot analysis. Results: Compared with Sham operation group, MI group showed increased LVMI and decreased LVEF P Conclusion: Losartan could increase ACE2 expression and therefore, inhibit Ang II expression and improve the ventricular remodeling in MI rats’ model.