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Objective To investigate the effects of brain-derived neurotrophic factor (BDNF) pretreatment on H9c2 myocardial hypoxia/reoxygenation (H/R) injury, and explore its mechanism. Methods The H9c2 myocardial cells were cul?tured in vitro and (95%O2+5%CO2) oxygen cultured 12 h after (95%N2+5%CO2) hypoxia cultured 4 h to establish the H/R model. The cells were divided into normal control group, H/R group, different concentrations (1, 10, 100μg/L) BDNF pre?treatment in H/R groups and TrkB-inhibitor group (with 100μg/L BDNF and 1∶1 000 TrkB inhibitor pre-treatment in H/R group). The cell survival rate was measured by MTT method in different groups. The lactate dehydrogenase (LDH), creatine kinase (CK), malondialdehyde (MDA) and superoxide dismutase (SOD) content and activity were detected after H/R injury. The apoptotic rate of H9c2 myocardial cells were detected by flow cytometry, and the expressions of TrkB, Bcl-2 and Bax protein were detected by Western blot assay. Results Compared with the normal control group, the survival rate of H9c2 myocardial cells was decreased significantly in H/R model group (P < 0.05), LDH, CK and MDA contents were increased and SOD activity was decreased (P<0.05). The cell apoptosis rate was increased significantly (P<0.05). The anti-apoptosis Bcl-2 protein expression was decreased, pro-apoptosis Bax protein expression was increased in H/R model group (P<0.05). Compared with the H/R model group, the cell survival rates of H9c2 myocardial cells were increased after pre-treatment with different concentrations of BDNF (P<0.05);LDH, CK and MDA contents were decreased and SOD activity were in?creased respectively (P < 0.05). The cell apoptotic rates were decreased (P < 0.05). The expressions of TrkB receptor and Bcl-2 protein gradually increased, while the expression of Bax protein was gradually decreased (P<0.05). The role of BDNF was inhibited by TrkB inhibitor. Conclusion BDNF pre-treatment can promote the cell survival rate of H9c2 myocardial cells after H/R injury, which plays a protective role by inhibiting the cell apoptotic rate and maintaining antioxidant capacity, and associates with BDNF-TrkB signaling pathways.
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Objective: To investigate the effect of tanshinone IIA (TSN) on left ventricular hypertrophy (LVH) and cardiomyocyte apoptosis in spontaneous hypertensive rats (SHRs). Methods: A total of 60 SHRs at 8 weeks of age were randomly divided into 3 group: Blank control group, the rats were sacriifced at 8 weeks, TSN group, the rats were treated with TSN at 1 ml/(kg?d) for 18 weeks and Solvent control group, the rats were treated with the solvent at 1 ml/(kg?d) for 18 weeks. n=20 in each group and 15 rats were used for the experiments. The systolic blood pressure (SBP) and left ventricular mass index (LVMI) were examined, cardiomyocyte’s diameter and surface area were measured by HE staining, the apoptosis rate was evaluated by TUNEL method and the apoptosis related protein expression s of Bcl-2, Bax and p53 were determined by Western blot analysis. Results: ①Compared with Solvent control group, TSN group had decreased LVMI (3.23 ± 0.24) mg/g vs (4.58 ± 0.68) mg/g,cardiomyocyte’s diameter (16.13 ± 1.77) μm vs (27.15 ± 3.52) μm and surface area (230.23 ± 69.37) μm2 vs (490.12 ± 118.96) μm2and decreased apoptosis rate (7.45 ± 1.78) % vs (10.61 ± 2.77) %, allP0.05. Conclusion: TSN could inhibit the development of LVH and decrease the cardiomyocyte apoptosis, which might be via up-regulating the protein expressions of Bcl-2 and down-regulating Bax and p53 in SHRs.
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[ABSTRACT]AIM:Tostudytheprotectiveeffectofbrain-derivedneurotrophicfactor(BDNF)onvascularendo-thelial cells with H 2 O2-induced oxidative injury .METHODS: Human umbilical vein endothelial cells ( HUVECs ) were cultured in vitro, and the oxidation injury model of HUVECs was established by treatment with H 2 O2 .The oxidatively in-jured HUVECs were cultured with different concentrations (1, 10 and 100μg/L) of BDNF.At the same time, the control group (no injury), PBS treatment after H2O2 injury group and TrkB inhibitor group (with 100 μg/L BDNF and 1∶1 000 TrkB inhibitor) were also set up.The viability of the HUVECs was detected by MTT assay .The levels of LDH, MDA, SOD and GSH were measured .The releases of NO , ET-1 and ICAM-1 were analyzed by ELISA .The changes of ROS pro-duction and cell apoptosis were evaluated by flow cytometry .The protein levels of TrkB , p-TrkB, cleaved caspase-3, Bcl-2 and Bax were determined by Western blot .RESULTS:Compared with uninjured control group , in H2 O2 oxidative injury plus PBS treatment group , the viability of the cells was decreased significantly , the LDH and MDA levels were increased significantly and the activities of SOD and GSH were decreased significantly .The NO secretion was decreased , and the ET-1 and ICAM-1 concentrations were increased significantly .The ROS content and apoptotic rate were increased significantly . The protein levels of cleaved caspase-3 and Bax were increased but Bcl-2 protein expression was decreased significantly . Compared with PBS treatment group , in H2 O2-injured HUVECs treated with different concentrations of BDNF , the cell via-bility was gradually increased , the LDH and MDA levels were decreased and the activities of SOD and GSH were increased gradually .The secretion of NO was increased but ET-1 and ICAM-1 were decreased gradually .The ROS content and apop-totic rate were decreased significantly .The TrkB and p-TrkB levels were significantly increased significantly , the protein expression of cleaved-caspase 3 and Bax was decreased gradually and the Bcl-2 protein expression increased gradually .The role of BDNF was inhibited by TrkB inhibitor .CONCLUSION:BDNF protects HUVECs from oxidative injury by binding with TrkB to activate the BDNF-TrkB signaling pathways .