Naringenin Attenuates Myocardial Injury By Regulating Ampk/Nrf2/HO-1 Signaling Pathways In Diabetic Mice

Objective: To investigate the protective effect of naringenin(NAR)on myocardial injury and the preliminary study about its possible mechanism of action adenosine monophosphate activated protein kinase(AMPK)/nuclear factor-E2-related factor 2(Nrf2)/ heme oxygenasel 1(HO-1)signaling pathway in type 1 diabetic mice.Methods: Fifty Healthy male mice(species C57BL/6,body weight 20.8±0.5)gram)were selected and fed with normal food and water for one week,then randomly divided into normal group(N group)and model group(M group).The mouse of type 1 diabetes mellitus(DM)was established by intraperitoneal injection of streptozotocin(STZ)The mark of model was successfully established when random blood glucose greater than 16.7mmol/L measured for 3 consecutive days.Mice in group M were modeled according to the above method.Then the M group mice were divided into diabetes group(D group),diabetes-low dose of NAR intervention group(D+L-NAR group),diabetes-middle dose of NAR intervention group(D+M-NAR group),diabetes-high dose of NAR intervention group(D+H-NAR group).In each intervention group Mice were given low-dose,medium-dose and high-dose NAR respectively by gavage,and the mice in N and D group were given the same volume of normal saline gavage as those in the D+M-NAR.once a day for 6 weeks.The mice were sacrificed at the end of the experiment,The effects of NAR at different doses on the blood glucose of type 1 DM mice were observed by intra-group longitudinal comparison and cross-group comparison.The histopathological changes of the cardiac tissue of type 1 DM mice were observed with HE staining.The degree of myocardial fibrosis in type 1 DM mice was observed with Masson staining measuring the myocardial collagen volume fraction(CVF)..The protein levels of interleukin-6(IL-6)and IL-10 in heart tissues of type 1 DM mice were observed by immunohistochemical staining.The apoptosis of myocardial cells in type 1 DM was evaluated by TUNEL staining and apoptosis rate calculation.The production of reactive oxygen species(ROS)in type 1 DM cardiomyocytes was determined by fluorescence probe of DHE.The content of malondialdehyde(MDA)and the activity of superoxide dismutase(SOD)in heart tissue were determined by the corresponding kit.The protein levels of p-AMPKα,AMPKα,Nrf2,HO-1,NAD(P)H: Quinone oxidoreductase 1(NQO1)and cleaved caspase-3 in heart tissue of type 1 DM were determined by Western blot.Results: There was no significant difference in blood glucose in group N between before and after self comparison while blood glucose of the D group and the NAR intervention group increased significantly after model formation.After NAR intervention,it was lower than that after modeling.Compared with N group,blood glucose of mice in group M was significantly increased,and compared with D group,blood glucose of mice in the NAR intervention group was decreased.Compared with N group,the myocardial cells were disordered,the blue-dyed collagen fibers were increased,the CVF,apoptotic rate and the protein levels of IL-6,cleaved caspase-3 were increased,while the protein levels of IL-10,p-AMPKα,Nrf2,HO-1,NQO1 and SOD activity were decreased,the ROS production rate and MDA content was increased significantly in D group(P< 0.05).Compared with D group,the myocardial cells were arranged neatly,and the blue staining collagen fibers were reduced,the CVF,apoptotic rate and the protein levels of IL-6,cleaved caspase-3 were relatively decreased,conversely the protein levels of IL-10,p-AMPKα,Nrf2,HO-1,NQO1 were increased in NAR intervention groups(P< 0.05).There was no significant difference in ROS production rate,MDA content and SOD activity between D group and D+L-NAR group.Compared with group D,the ROS production rate in D+M-NAR group and D+H-NAR group decreased,MDA content decreased and SOD activity increased(P<0.05).Conclusion: 1.The myocardial injury in type 1 diabetic mice was related to oxidative stress,inflammatory injury,myocardial fibrosis and excessive apoptosis.2.NAR can reduce myocardial oxidative stress,inflammatory damage,myocardial fibrosis and myocardial cell apoptosis in type 1 DM miceand reduce blood glucose;3.The reduction of myocardial injury in type 1DM mice by NAR may be related to the activation of AMPK/ NRF2 /HO-1signaling pathway.