RESUMO
Ischemia-reperfusion (IR) is one of the significant medical problems in China. Triphenyltetrazolium chloride (TTC) staining is used to detect the status of the infarct size, and real-time PCR and western blotting are used to detect expressions of genes. TUNEL assay has been used to detect apoptosis. Using a tree shrew myocardial IR model, we found that in the reperfusion period, resina draconis (RD) treatment reduced the infarct size by TTC staining, and significantly enhanced the superoxide dismutase expression and down-regulated the malondialdehyde concentration in a dose-dependent manner. In hearts showing IR, Bax was increased and Bcl-2 was reduced, and RD treatment inhibited the IR-induced Bax expression and up-regulated the IR suppressed level of Bcl-2. TUNEL assay showed that IR induced the apoptosis of myocardial cells, and RD treatment suppressed the IR-induced apoptosis. CHOP and GRP78 were also upregulated in IR hearts, and RD treatment could significantly attenuate the CHOP and GRP78 levels compared with IR group. We further found that IR decreased the miR-423-3p expression and upregulated its target gene ERK both in mRNA and protein levels, and RD treatment upregulated miR-423-3p expression and downregulated ERK expression compared with the IR group. Importantly, miR-423-3p mimics inhibited IR increased ERK, CHOP and GRP78 expressions, and enhanced IR decreased Bcl-2 expression, and inhibited the IR-induced apoptosis of myocardial cells. The findings of this study suggest that RD treatment inhibited the endoplasmic reticulum induced apoptosis of myocardial cells via regulating miR-423-3p/ERK signaling pathway in a tree shrew myocardial IR model.
Assuntos
Cardiotônicos/farmacologia , Dracaena/química , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Miócitos Cardíacos/efeitos dos fármacos , Resinas Vegetais/farmacologia , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Cardiotônicos/isolamento & purificação , Modelos Animais de Doenças , Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/genética , Retículo Endoplasmático/metabolismo , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Regulação da Expressão Gênica , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Masculino , Malondialdeído/antagonistas & inibidores , Malondialdeído/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/genética , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Traumatismo por Reperfusão Miocárdica/genética , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/patologia , Miocárdio/metabolismo , Miocárdio/patologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Resinas Vegetais/isolamento & purificação , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Fator de Transcrição CHOP/genética , Fator de Transcrição CHOP/metabolismo , Tupaiidae , Proteína X Associada a bcl-2/genética , Proteína X Associada a bcl-2/metabolismo , Proteína de Morte Celular Associada a bcl/genética , Proteína de Morte Celular Associada a bcl/metabolismoRESUMO
Diabetic cardiomyopathy (DCM) is a form of idiopathic heart disease, with signs including hypertrophy of myocardial cells, hypertensionindependent fibrosis and coronary artery disease. Considering the involvement of dimethylarginine dimethylaminohydrolase 2 (DDAH2) in diabetes, it was hypothesized that DDAH2 may be beneficial to cardiac function and myocardial fibrosis during the progression of DCM with involvement of the DDAH/asymmetric NG, NGdimethylLarginine (ADMA)/nitric oxide synthase (NOS)/nitric oxide (NO) signaling pathway. Following establishment of diabetic rat models, diabetesrelated blood biochemical indices and cardiac function were measured in diabetic rats treated with lentivirus expressing DDAH2, short hairpin RNA against DDAH2, or LNNA (inhibitor of NOS) to identify the roles of DDAH2 in DCM. The functional roles of DDAH2 in DCM were further determined through detection of the levels of collagen I, matrix metalloproteinase 2 (MMP2) and tissue inhibitor of metalloproteinase 2 (TIMP2). The H9C2 myocardial cell line was selected for in vitro experiments. The effects of DDAH2 on the migration of myocardial cells under high glucose conditions were also examined. To further investigate the underlying regulatory mechanism of DDAH2 in DCM, the contents of ADMA and NO, and the activities of DDAH and NOS were observed. The DCM model rats treated with DDAH2 exhibited reduced left ventricular enddiastolic pressure, and decreased blood glucose, total cholesterol, triglyceride, fasting blood glucose, and fasting insulin levels, but exhibited increased left ventricular systolic pressure and maximum rate of left ventricular pressure rise/fall levels in myocardial tissues. Myocardial cells under high glucose conditions treated with DDAH2 showed reductions in collagen I, MMP2 and TIMP2, indicating that DDAH2 reduced cell migration. Decreased levels of ADMA and NO but increased levels of DDAH and NOS were observed following treatment with DDAH2, indicating that the DDAH/ADMA/NOS/NO pathway was activated. These results reveal that the overexpression of DDAH2 attenuates myocardial fibrosis and protects against DCM through activation of the DDAH/ADMA/NOS/NO pathway in DCM rats. These results indicate that DDAH2 is a potential therapeutic candidate for the treatment of DCM.
