Down-regulation of miR-153-3p attenuates H2O2-induced H9C2 cell injury by promoting Nrf2 expression

AIM To study the effect of microRNA-153-3p (miR-153-3p) knock-down on oxidative injury of H9C2 cells induced by H₂O₂ and its specific mechanism. METHODS The oxidative stress injury of H9C2 cell model was induced by H₂O₂, and then the cell viability and the expression of miR-153-3p were detected by MTT assay and RT-qPCR, respectively. The effects of miR-153-3p knock-down on the H9C2 cell injury under oxidative stress were studied by RNA interference technology. The targets of miR-153-3p were identified by Western blot and dual-luciferase reporter assay. RESULTS MTT assay showed that the viability of H9C2 cells was decreased with the increase in H₂O₂ concentration (P<0.05). The results of RT-qPCR showed that the expression of miR-153-3p was increased with the increase in H₂O₂ concentration (P<0.05). Knock-down of miR-153-3p increased the viability of H9C2 cells under oxidative stress, decreased the cell apoptosis and the content of malondialdehyde (MDA), and increased the activity of superoxide dismutase (SOD). The expression of nuclear factor E2-related factor 2（Nrf2） and antioxidant response element（ARE） activity were increased with the increase in H₂O₂ concentration (P<0.01). TargetScan analysis and dual-luciferase reporter assay showed that Nrf2 was one of the potential target genes of miR-153-3p. The results of Western blot further showed that over-expression of miR-153-3p inhibited the expression of Nrf2 (P<0.01), while down-regulation of miR-153-3p increased the expression of Nrf2 (P<0.01). Dual interference with Nrf2 and miR-153-3p significantly reduced H9C2 cell viability, promoted the apoptosis, increased MDA content, and decreased SOD activity in the presence of H₂O₂ (P<0.01). CONCLUSION Inhibition of miR-153-3p expression attenuates the injury of H9C2 cells induced by H₂O₂ through up-regulating Nrf2/ARE signaling pathway.     

Protective effect of BNDF on vascular endothelial cells with H2O2-induced oxidative injury

AIM: To study the protective effect of brain-derived neurotrophic factor (BDNF) on vascular endothelial cells with H₂O₂-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 H₂O₂. The oxidatively injured HUVECs were cultured with different concentrations (1, 10 and 100 μg/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 production 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 H₂O₂ 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 H₂O₂-injured HUVECs treated with different concentrations of BDNF, the cell viability 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 apoptotic 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.     

Role of ghrelin in cell protection by up-regulating HSP70 through ERK1/2 signaling pathway in PC12 cells

AIM:To study the role of ghrelin in cell protection by up-regulating heat shock protein 70 (HSP70) and inhibiting apoptosis induced by oxidative stress through extracellular regulated protein kinases 1/2 (ERK1/2) signaling pathway in the PC12 cells. METHODS:Sodium nitoprusside (SNP) was used to induce oxidative stress injury in the PC12 cells. The cultured PC12 cells were divided into SNP-injured group (incubated with SNP at 0.5 mmol/L for 6, 12, 18 and 24 h), ghrelin pretreatment group (ghrelin at 100 nmol/L was given 30 min before adding SNP); HSP70 inhibitor group (quercetin at 10 μmol/L was added 60 min before ghrelin treatment), ERK inhibitor group (ERK 1/2 inhibitor PD98059 was added 60 min before ghrelin treatment) and control group (added same amount of culture medium only). The apoptotic rate was detected by flow cytometry. The protein expression was determined by Western blot and immunocytochemistry. RESULTS:Compared with control group, the apoptotic rate of PC12 cells in SNP-injured group was significantly increased (P<0.05). Compared with SNP-injured group, ghrelin (100 nmol/L) pretreatment significantly inhibited SNP-induced apoptosis of PC12 cells (P<0.05), and significantly up-regulated the protein expression of HSP70 (P<0.05). Time-effect analysis showed that ghrelin had the most significant effect at 18 h after SNP injury. Quercetin, an inhibitor of HSP 70, significantly reduced the anti-apoptotic effect of ghrelin (P<0.05). Ghrelin pretreatment promoted the phosphorylation of ERK1/2. ERK1/2 inhibitor PD98059 significantly inhibited the effects of ghrelin on up-regulation of HSP70 expression (P<0.05). CONCLUSION:Ghrelin upregulates the expression of HSP70 and inhibits the apoptosis in the PC12 cells induced by oxidative stress by promoting the phosphorylation of ERK1/2.     

Trx-1 over-expression attenuates oxidative stress injury in MPP+ -induced PC12 cells by regulating NF-κB signaling pathway

AIM:To investigate the inhibitory effect of thioredoxin 1 (Trx-1) over-expression on oxidative stress injury in 1-methyl-4-phenylpyridinium (MPP⁺)-induced rat pheochromocytoma PC12 cells by regulating NF-κB signaling pathway.METHODS:The PC12 cells were damaged by treatment with MPP⁺ at 1, 3 and 5 mmol/L, and the optimal concentration of 3 mmol/L was selected. The cell viability was measured by MTT assay. The oxidative stress indexes lactate dehydrogenase (LDH) activity, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in the cell culture supernatant were detected, and the protein expression of Trx-1 was determined by Western blot. Lentiviral infection with Ad-Trx-1-GFP sequence was used to establish a model of MPP⁺-treated PC12 cells with Trx-1 over-expression. The effects of Trx-1 over-expression on the cell viability, oxidative stress responses and NF-κB signaling pathway were determined by MTT assay, commercial kits and Western blot. The effects of phorbol 12-myristate 13-acetate (PMA), an activator of NF-κB signaling pathway, on the viability and oxidative stress of PC12 cells were observed. The NF-κB signaling pathway inhibitor pyrrolidine dithiocarbamate (PDTC) was used in MPP⁺-treated PC12 cells with Trx-1 over-expression, and the cell viability and oxidative stress responses were measured. RESULTS:The viability of PC12 cells, SOD activity in the supernatant and protein expression of Trx-1 were decreased, while LDH activity and MDA content in the supernatant were increased significantly by treatment with MPP⁺ at 1, 3 and 5 mmol/L. The effect of MPP⁺ at 3 mmol/L and 5 mmol/L was significantly greater than that at 1 mmol/L (P<0.05), and no significant difference between 3 mmol/L and 5 mmol/L was observed (P>0.05). The inhibitory effect of MPP⁺ on the viability of PC12 cells, and the oxidative stress injury and activation of NF-κB signaling pathway induced by MPP⁺ were significantly attenuated by over-expression of Trx-1. The inhibitory effect of MPP⁺ on the viability of PC12 cells and the oxidative stress injury induced by MPP⁺ were promoted by the activation of NF-κB signaling pathway, while the protective effects of Trx-1 over-expression on the MPP⁺-treated PC12 cells were enhanced by the inhibition of NF-κB signaling pathway. CONCLUSION:Over-expression of Trx-1 protects MPP⁺-treated PC12 cells from oxidative stress injury by regulating NF-κB signaling pathway.     

Effect of sinapine on H2O2-induced adipogenic differentiation of bone marrow mesenchymal stem cells

AIM:To investigate the effects of sinapine, an effective monomer of Chinese medicine, on hydrogen peroxide (H₂O₂)-induced adipogenic differentiation of bone marrow mesenchymal stem cells (BMSCs).METHODS:The undifferentiated rat BMSCs were identified and screened by flow cytometry. The adipogenic differentiation of BMSCs was induced by H₂O₂, and the toxicity of sinapine on BMSCs was tested by CCK-8 assay. After the modeling method and the concentration range of sinapine were determined, the lipid droplets in the cells were detected by Oil Red O semi-quantitative assay, and the optimal drug concentration was selected. Finally, Oil Red O assay was observed 24 h after drug intervention, and the expression of adipogenic differentiation-related proteins, adipocyte protein 2 (aP2), peroxisome proliferator-activated receptor γ (PPARγ) and glucose transporter 4 (Glut4), at mRNA and protein levels in the BMSCs was determined by qPCR and Western blot.RESULTS:Treatment with H₂O₂ at 200 μmol/L for 1 h induced BMSCs to differentiate into adipocytes. Below the concentration of 40 μmol/L, sinapine had no toxicity to BMSCs. The best inhibitory concentration of sinapine on adipogenic differentiation was at 15 μmol/L. The number of lipid droplets in sinapine (15 μmol/L) group was significantly lower than that in model group. In sinapine group, the expression of aP2, PPARγ and Glut4 at mRNA and protein levels was lower than that in model group (P<0.01).CONCLUSION:Sinapine inhibits H₂O₂-induced adipogenic differentiation of rat BMSCs. The mechanism may be related to the PPARγ/AMPK signaling pathway.     

Minocycline suppresses sodium nitroprusside-induced apoptosis in PC12 cells by regulating PI3K/Akt signaling

AIM：To explore the role of PI3K/Akt signaling in the anti-apoptotic effect of minocyline (MC) on the apoptosis of PC12 cells induced by sodium nitroprusside (SNP). METHODS：PC12 cells were divided into 4 groups: blank control group, SNP (500 μmol/L) group, MC (10 μmol/L)+SNP group and LY294002+MC+SNP group. The cell viability was observed by MTT assay. The expression of Akt and p-Akt was determined by Western blotting. RESULTS： The viability of the PC12 cells decreased after exposed to 500 μmol/L SNP for 24 h. Meanwhile, MC at concentration of 10 μmol/L significantly blocked the effect of SNP, such as decreasing the cell viability. Pretreatment with LY294002 for 60 min prior to exposure of the PC12 cells to MC and SNP down-regulated the expression of p-Akt induced by SNP. CONCLUSION：Minocycline regulates PI3K/Akt signaling pathway to restrain the apoptosis of PC12 cells induced by SNP.     

Effects of iPSC-MSCs on mitochondria of PC12 cells injured by CoCl2

AIM: To investigate the effects of induced pluripotent stem cells-derived mesenchymal stem cells (iPSC-MSCs) on cobalt chloride (CoCl₂)-induced injuries of PC12 cells and its possible mechanism. METHODS: PC12 cells were exposed to CoCl₂ to set up a chemical-induced cellular injury model and were cocultured with iPSC-MSCs. The cell viability was tested by CCK-8 assay. The apoptosis was measured by flow cytometry using Annexin V/PI staining. The mitochondrial membrane potential (MMP) was analyzed by flow cytometry using JC-1 staining. Immunofluorescence was employed to observe mitochondrial transfer from iPSC-MSCs to PC12 cells. RESULTS: Apoptosis of PC12 cells was increased and MMP of PC12 cells was decreased after exposed to CoCl₂ at concentration of 400 μmol/L for 24 h. Coculture of PC12 cells with iPSC-MSCs reduced the apoptosis and recovered the MMP of the PC12 cells. Tunneling nanotubes were formed between iPSC-MSCs and PC12 cells, through which the iPSC-MSCs transferred the mitochondria to the PC12 cells. CONCLUSION: iPSC-MSCs protect PC12 cells from CoCl₂-induced injuries, which may be associated with the mitochondrial transfer from iPSC-MSCs to PC12 cells.     

USP14 regulates H2O2 induced oxidative stress in H9c2 cells

AIM:To evaluate the effect of inhibiting ubiquitin-specific protease 14(USPl4) activity on oxidative stress induced by H₂O₂ of H9c2 cells.METHODS:The H9c2 cells were incubated with H₂O₂ at 25 μmol/L for 2 h to establish the oxidative stress injury model.The cells were divided into control group,H₂O₂ group,IU1 group (25 μmol/L or 50 μmol/L) and IU1+H₂O₂ group.The H9c2 cells activity was measured by MTS assay.The level of intracellular reactive oxygen species (ROS) and cell survival rate were analyzed by flow cytometry assay.The changes of the mitogen-activated protein kinase (MAPK) family related proteins were detected by Western blot.RESULTS:Compared with control group,the cell activity and the viability rate in H₂O₂ group were decreased (P<0.05),while the intracellular ROS,the protein levels of Bax/Bcl-2,P53,p-ERK1/2,p-JNK and p-P38 were increased (P<0.05).Compared with H₂O₂ group,the cell activity and the viability rate of the H9c2 cells in IU1+H₂O₂ group were increased (P<0.05),while the intracellular ROS,the protein levels of Bax/Bcl-2,P53,p-ERK1/2,p-JNK and p-P38 were decreased (P<0.05).CONCLUSION:Inhibition of USPl4 activity reduces the oxidative stress injury of the H9c2 cells.The mechanism may be related to inhibition of the MAPK signaling and down-regulation of apoptosis related proteins.     

Effect of shikonin on high glucose-induced apoptosis and oxidative stress in vascular endothelial cells

AIM:To investigate the effect of shikonin on the apoptosis and oxidative stress induced by high concentration of glucose in vascular endothelial cells. METHODS:Rat thoracic aortic endothelial cells were randomly divided into 5 groups:normal control group (with glucose at concentration of 5.5 mmol/L in cell culture medium), high glucose group (with glucose at concentration of 33 mmol/L in cell culture medium), high glucose+low shikonin group (with glucose at concentration of 33 mmol/L and shikonin at concentration of 0.1 μmol/L in cell culture medium), high glucose+medium shikonin group (with glucose at concentration of 33 mmol/L and shikonin at concentration of 1 μmol/L in cell culture medium), and high glucose+high shikonin group (with glucose at concentration of 33 mmol/L and shikonin at concentration of 10 μmol/L in cell culture medium). After treatments, the cell viability was measured by CCK-8 assay and cell apoptotic rate was analyzed by flow cytometry. In addition, the status of oxidative stress was evaluated by determining the levels of malondialdehyde (MDA), reactive oxygen species (ROS), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). The activation of Nrf2/HO-1 signaling pathway was determined by Western blot. RESULTS:Compared with high glucose group, shikonin reversed high glucose-induced decrease in cell viability and increase in apoptosis in a concentration-dependent manner. High concentration of glucose induced high levels of MDA and ROS, while decreased the levels of SOD and GSH-Px. However, after treatment with shikonin, the contents of MDA and ROS were decreased, while the activities of SOD and GSH-Px were increased as compared with high glucose group. Furthermore, the high concentration of glucose up-regulated the protein levels of cleaved caspase-3, HO-1 and Nrf2 (nuclear). Compared with high glucose group, the protein levels of cleaved caspase-3, HO-1 and Nrf2 (nuclear) were partly decreased after treatment with shikonin. CONCLUSION:Shikonin alleviates high glucose-induced vascular endothelial cell apoptosis. Its mechanism may be related to activation of Nrf2/HO-1 signaling pathway and down-regulation of oxidative stress in vascular endothelial cells.     

Zerumbone attenuates MPP+-induced cytotoxicity in human neuroblastoma SH-SY5Y cells by inhibition of oxidative stress

AIM: To investigate the role of zerumbone (ZER) in 1-methyl-4-phenylpyridinium (MPP⁺)-induced cytotoxicity of human neuroblastoma SH-SY5Y cells. METHODS: Human neuroblastoma SH-SY5Y cells were cultured in vitro and the protective effect of ZER against MPP⁺-induced cytotoxicity was measured by CCK-8 assay. Flow cytometry was used to determine the apoptosis and reactive oxygen species (ROS). The expression of Parkinson disease protein 7 (PARK7) was knocked-down by using PARK7-specific short hairpin RNA (shRNA). The protein levels of PARK7, nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were determined by Western blot. RESULTS: MMP⁺ remarkably reduced the cell viability in a dose-dependent and time-dependent manner. The SH-SY5Y cell injury model was established by treatment with MPP⁺ at 600 μmol/L for 24 h. ZER up-regulated the protein levels of PARK7 and Nrf2 (P<0.05), alleviated apoptosis (P<0.05), and reduced ROS production (P<0.05) in the SH-SY5Y cell injury model. Meanwhile, N-acetyl-L-cysteine (NAC) had the similar functions. Moreover, significant reductions in the protein levels of Nrf2 and HO-1 (P<0.05), and obvious increases in apoptosis (P<0.05) and ROS level (P<0.05) were demonstrated in PARK7-knockdown cells. CONCLUSION: ZER protects SH-SY5Y cells against MPP⁺-induced cytotoxi-city, which may be related to activation of PARK7/Nrf2/HO-1 pathway, and subsequent attenuation of oxidative stress and apoptosis.     

Effect of miRNA-21 on protection of PC12 cells from oxygen-glucose deprivation damage

AIM: To investigate the effect of microRNA (miRNA)-21 on the PC12 cells with hypoxic-ischemic damage.METHODS: The PC12 cells were cultured in vitro, and the cell model of oxygen-glucose deprivation (OGD) was established. In accordance with the following requirements, the cells were randomly divided into control group, OGD group, negative control sequence+OGD group, miRNA-21 inhibitor+OGD group and miRNA-21 mimic+OGD group. The effects and mechanism of miRNA-21 on the protection of PC12 cells from OGD damage were determined by CCK-8 assay, real-time PCR and Western blot.RESULTS: Decrease in the expression of miRNA-21 by transfection with miRNA-21 inhibitor inhibited the viavility of the PC12 cells subjected to OGD damage. Increase in the expression of miRNA-21 by transfection with miRNA-21 mimic promoted the viability of the PC12 cells subjected to OGD damage. It was further confirmed that miRNA-21 promoted the AKT phosphorylation in OGD-damaged PC12 cells.CONCLUSION: miRNA-21 significantly increases the viability of PC12 cells subjected to OGD damage, which may be related to the activation of PI3K/AKT signaling pathway.     

Effect of senegenin on H2O2-induced damage in hippocampal neurons of SD rats

AIM: To observe the effect of senegenin (Sen) on hippocampal neuron injuries induced by H₂O₂.METHODS: Hippocampal neurons were isolated from neonatal SD rats. The primarily cultured neurons were divided into control group, H₂O₂ group, Sen group and Sen+H₂O₂ group. The cell viability, the content of malondialdehyde(MDA) and the activity of superoxide dismutase(SOD) in the neurons were detected after treated with Sen. The morphological changes of nucleus of the neurons were observed by Hoechst 33258 staining. The mRNA expression of bcl-2 and bax was quantified by real-time PCR. The protein levels of Bcl-2 and bax were measured by Western blotting. The activity of caspase-3 was also assayed.RESULTS: Compared with H₂O₂ group, the levels of antioxidative enzyme were increased in Sen+H₂O₂ group (P<0.05). In addition, mRNA expression of bcl-2 increased and that of bax decreased (P<0.05) in Sen+H₂O₂ group. Moreover, Sen increased the protein level of Bcl-2, and reduced the protein level of Bax and the activity of caspase-3 in the neurons exposed to H₂O₂ (P<0.05).CONCLUSION: The protective effect of Sen on hippocampal neurons with H₂O₂ -induced injury may be involved in the mechanisms of     

Effect of hydrogen molecule on apoptosis-related proteins and Nrf2 signaling pathway in glomerular mesangial cells cultured with high glucose

AIM: To investigate the role of hydrogen molecule on apoptosis-related proteins in glomerular mesangial cells cultured with high glucose and to explore its possible mechanism. METHODS: Mouse glomerular mesangial cells cultured in vitro were divided into 4 groups:normal control group (C group, 5.5 mmol/L glucose), mannitol group (G group, 5.5 mmol/L glucose+19.5 mmol/L mannitol), high glucose group (H group, 25 mmol/L glucose), high glucose+hydrogen-rich water group (HH group, 25 mmol/L glucose+hydrogen-rich water), and cultured for 48 h. The protein levels of Bax, Bcl-2, cleaved caspase-3, nuclear factor E2-related factor-2 (Nrf2), heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase-1 (NQO-1) were determined by Western blot, and the mRNA expression of HO-1 and NQO-1 was determined by RT-PCR. The level of intracellular reactive oxygen species (ROS) was detected by dihydroethidium method, and the activity of superoxide dismutase (SOD) was measured by WST-8 assay. RESULTS: Compared with C group, the protein levels of Bax and cleaved caspase-3 were up-regulated, and Bcl-2 was down-regulated in H group (P <0.05). No significantly difference of the protein levels mentioned above between C and HH group was observed. Compared with H group, the protein levels of Bax and cleaved caspase-3 were down-regulated, and Bcl-2 was up-regulated in HH group (P <0.05). The level of intracellular ROS was higher and the activity of SOD was lower in H group than those in C group (P<0.05). However, there was no difference of the SOD activity between C group and HH group. The level of intracellular ROS decreased and the activity of SOD increased in HH group as compared with H group (P<0.05). Compared with C group, clearly reduced protein expression of Nrf2, HO-1 and NQO-1, and decreased mRNA expression of HO-1 and NQO-1 in H group were observed (P<0.05). Compared with H group, the protein levels of Nrf2, HO-1 and NQO-1 as well as the mRNA levels of HO-1 and NQO-1 were obviously increased in HH group (P<0.05).CONCLUSION: Hydrogen molecule inhibits the expression of pro-apoptotic proteins and induces the expression of anti-apoptotic proteins in glomerular mesangial cells cultured with high glucose. The mechanism may be related to activation of Nrf2 signaling pathway.     

Limb ischemic preconditioning protects human umbilical vein endothelial cells from oxidative stress induced by H2O2

AIM: To investigate the effects of the sera from the rats after limb ischemic preconditioning (LIPC) on human umbilical vein endothelial cells (HUVECs) injured by hydrogen peroxide (H₂O₂). METHODS: The HUVECs were divided into 5 groups: the cells in control group were cultured without any intervention; the cells in model group (M) were damaged by 1 mmol/L H₂O₂ for 2 h; the cells in early preconditioning serum (EPS) group, delayed preconditioning serum (DPS) group or sham limb ischemic preconditioning serum (SPS) group were treated with the corresponding serum at 5% for 12 h, respectively, and then treaed with H₂O₂ for 2 h. The viability of the HUVECs was analyzed by flow cytometry. The lactate dehydrogenase (LDH) in the culture media was detected. The cell adhesion molecules in the HUVECs were detected by real-time PCR. The mRNA and protein expression of heme oxygenase-1 (HO-1) was also determined. RESULTS: The viability of HUVECs incubated with 1 mmol/L H₂O₂ for 2 h significantly decreased compared with the control cells, which was accompanied with the augmentations of LDH in the medium and the cell adhesion molecules in cells, such as vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1). Preincubation with EPS and DPS derived from the rats subjected LIPC attenuated these injuries. Furthermore, pretreatment with EPS and DPS increased the expression of HO-1 at mRNA and protein levels. CONCLUSION: LIPC protects the HUVECs from H₂O₂-induced injury.     

Naringenin attenuates myocardial injury by regulating AMPK/Nrf2/HO-1 signaling pathways in diabetic mice

AIM: To investigate the effects of naringenin (NAR) on the myocardium as well as its effects on adenosine monophosphate-activated protein kinase (AMPK)/nuclear factor (NF)-E2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) signaling pathways in diabetic mice. METHODS: C57BL/6 mice (n=50) were randomly divided into normal group (N group) and model group. The mouse model of type 1 diabetes mellitus was established by intraperitoneal injection of streptozotocin (STZ), then the 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) and diabetes+high dose of NAR intervention group (D+H-NAR group). The mice in intervention groups were received NAR at low, middle and high doses respectively by gavage, and the mice in N group and D group were received equal volume of normal saline. After 6 weeks, the mice were sacrificed to observe the effects of NAR at different doses on the body weight and blood glucose. The histopathological changes of the cardiac tissues were observed with HE staining. The myocardial collagen volume fraction (CVF) was calculated by Masson staining. Immumohistochemical staining was used to test the protein levels of interleukin-6 (IL-6) and IL-10, and the TUNEL was used to observe the apoptosis of myocardial tissues. The production of reactive oxygen species (ROS) in the myocardial cells was analyzed by fluorescence probe of DHE, and superoxide dismutase (SOD) activity and malondiodehyde (MDA) content in the myocardial cells were measured by SOD and MDA kits. Western blot was applied to determine the protein levels of p-AMPKα, AMPKα, Nrf2, HO-1, NAD(P)H:quinone oxidoreductase 1 (NQO1) and cleaved caspase-3 in the myocardial tissues. RESULTS: Compared with N group, the blood glucose of the mice in D groups was increased and the body weight was decreased significantly. Compared with D group, the blood glucose of the mice in NAR intervention groups was decreased and the body weight was increased. Compared with N group, 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 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). No significantly difference of the ROS production rate, SOD activity and MDA content between D group and D+L-NAR group was observed. However, the ROS production rate and MDA content was decreased,SOD activity were increased in D+M-NAR group and D+H-NAR group as compared with D group. CONCLUSIONS: NAR attenuates myocardial injury in diabetic mice, and its mechanism may be related to regulation of AMPK/Nrf2/HO-1 signaling pathway, enhancement of the antioxidant reaction, reduction of myocardial fibrosis, apoptosis and inflammation.     

Salvianolate attenuates oxidative stress injury of human endothelial EA.hy926 cells induced by hydrogen peroxide

AIM: To investigate the effect of salvianolate on oxidative damage induced by hydrogen peroxide in human endothelial EA.hy926 cells.METHODS: EA.hy926 cells were cultured in vitro and divided into the following groups:control group, damage group, and anti-damage groups (salvianolate+damage groups). The cell viability was measured by CCK-8 assay. The migration ability of the EA.hy926 cells was detected by Transwell assay. The content of nitric oxide (NO) in the culture supernatant of the EA.hy926 cells was examined. The levels of vascular endothelial growth factor (VEGF) were detected by ELISA. The apoptosis,mitochondrial membrane potential and intracellular superoxide anion content of the EA.hy926 cells were analyzed by flow cytometry. The protein levels of caspase-3, cleaved caspase-3, Bcl-2, Bax, NF-κB and p53 were determined by Western blot. RESULTS: Compared with damage group, the viability of EA.hy926 cells pretreated with salvianolate at different concentrations was significantly increased (P<0.05). The apoptotic rate was significantly decreased (P<0.05). Savianolate enhanced the migration ability of the cells. The levels of VEGF, NO and mitochondrial transmembrane potential were increased (P<0.05), and the intracellular ROS level was significantly decreased (P<0.05). The protein levels of NF-κB, p53, Bax and cleaved caspase-3 were significantly decreased, and the protein level of Bcl-2 was markedly increased(P<0.05). CONCLUSION: Savianolate reduces the damage of EA.hy926 cells by hydrogen peroxide exposure, and its mechanism may be related to the blocking of NF-κB signaling pathway.     

Inhibitory effect of quercetin on apoptosis of PC12 cells induced by rotenone

AIM: To observe the effects and mechanisms of quercetin on the apoptosis of PC12 cells induced by rotenone. METHODS: PC12 cells were used in the study. Quercetin at the concentration of 300 μmol/L was added into the PC12 cells cultured in DMEM-F12 medium with 10% fetal calf serum. The morphological changes of the cells were observed under fluorescence microscope. The apoptotic rate was determined by flow cytometry assay. The protein levels of Bax and Bcl-2 were determined by Western blotting, and the mitochondrial membrane potential was measured by ratiometric probe JC-1.RESULTS: In the cells treated with rotenone+quercetin, the morphology of the cells was significantly improved, and the apoptotic rate was decreased to 6.7%, significantly lower than that in the cells treated with rotenone alone (P<0.01). The expression of Bcl-2 was up-regulated and Bax was down-regulated in rotenone+quercetin group (P<0.01), while the mitochondrial membrane potential was also increased (P<0.01) as compared to those in rotenone group.CONCLUSION: Pretreatment of quercetin inhibits the development of apoptosis in PC12 cells induced by rotenone. One of the mechanisms may be correlated with up-regulating the expression of Bcl-2 and down-regulating the expression of Bax, thus maintaining mitochondrial membrane potential.     

Bone marrow-derived mesenchymal stem cells protect against hypoxia-induced injury and apoptosis of PC12 cells via up-regulation of erythropoietin expression

AIM： To investigate the effects of bone marrow-derived mesenchymal stem cells (BM-MSCs) on cobalt chloride (CoCl2)-induced injury and apoptosis of PC12 cells. METHODS：PC12 cells were divided into control group, CoCl2 group, BM-MSCs-siCTL+CoCl2 group and BM-MSCs-siEPO+CoCl2 group. The viability of the PC12 cells was measured by MTT assay. Flow cytometry and Hoechst 33258 staining were used to determine the apoptotic rate and the changes of chromatin distribution in PC12 cells. The expression of erythropoietin (EPO) in BM-MSCs was measured by RT-PCR and Western blotting. The mRNA expression of Bcl-2 and Bax in PC12 cells was detected by RT-PCR. Caspase-9 and caspase-3 assay kits were used to detect the activity of caspase-9 and caspase-3. RESULTS：The viability of PC12 cells treated with CoCl2 for 24 h and 48 h decreased to （43.0±6.4）% and （33.8±5.7）%, respectively, while 1∶15 ratio of BM-MSCs co-culture increased the cell viability to （77.9±3.8）% and （75.2±9.7）%,respectively. The expression of EPO in BM-MSCs was up-regulated after treated with 0.6 mmol/L CoCl2 for 24 h and 48 h, while EPO siRNA significantly abrogated the EPO expression in BM-MSCs. BM-MSCs-siCTL co-culture significantly inhibited the apoptosis of PC12 cells induced by CoCl2. However, EPO siRNA the protective effect of BM-MSCs. Compared with CoCl2 treatment group, BM-MSCs co-culture induced remarkable increase in the expression of Bcl-2 and decrease in the expression of Bax in PC12 cells, which was reversed by EPO siRNA. BM-MSCs-siCTL co-culture remarkably abrogated the CoCl2 induced up-regulation of caspase-9 and -3, while BM-MSCs-siEPO co-culture significantly reversed the down-regulation of caspase-9 and -3 induced by BM-MSCs-siCTL co-culture. CONCLUSION：BM-MSCs protect PC12 cells from apoptosis induced by CoCl2. The protective effect of BM-MSCs might be executed by up-regulating the expression of EPO.     

Adiponectin attenuates H2O2-induced SH-SY5Y cell injury and tau hyperphosphorylation via activating PP2A

AIM: To study the effects of adiponectin on H₂O₂-induced cell injury and tau hyperphosphorylation in human neuroblastoma SH-SY5Y cells. METHODS: Cell viability was determined by MTT assay. H₂O₂-induced cell injury and morphological changes in the SH-SY5Y cells with or without adiponectin treatment were observed. The level of tau phosphorylation as well as the activities of protein phosphatase 2A(PP2A) and of glycogen synthase kinase-3β(GSK-3β) were examined by Western blotting. RESULTS: Adiponectin significantly attenuated H₂O₂-induced cell injury(P<0.01). Adiponectin upregulated the activity of PP2A and decreased phosphorylation levels of tau under the stimulation with H₂O₂ (P<0.01). Okadaic acid, a specific inhibitor of PP2A, blocked the protective effects of adiponectin(P<0.01). Adiponectin increased the phosphorylation level of GSK-3β at Ser9 site under H₂O₂ stimulation(P<0.01). CONCLUSION: Adiponectin protects SH-SY5Y cells against H₂O₂-induced cell injury and decreases tau hyperphosphorylation by activating PP2A and inactivating GSK-3β.