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1.
AIM and METHODS: The effects of hydrogen peroxide on Na+ currents were studied in freshly dissociated rat hippocampal CA1 neurons using the whole-cell patch-clamp techinique. RESULTS: ①H2O2 caused a dose-dependent and voltage-dependent increase in the voltage-activated Na+ currents. The amplitudes of Na+ currents were increased (48.0±4.2)% and (88. 2±5. 1)% (n=10) by H2O2 at 10 μmol/L and 100 μmol/L, respectively. ②H2O2 (10 μmol/L) did not affect the activation process, but changed the inactivation process significantly. Before and after application of 10 μmol/L of H2O2, the half-inactivation voltage was (-64.58±1.22)mV and (-53.55±0.94)mV (n=10, P<0.01), but the slope factor was not changed. CONCLUSION: As a product of oxidation metabolism, H2O2 is related to some diseases in the central nervous system.  相似文献   

2.
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.  相似文献   

3.
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4.
AIM: To investigate the ability of a metal complex ammonium tetrathiomolybdate (ATTM) to release H2S and its cytoprotective effect on an oxidative injury model. METHODS: Released H2S was absorbed in a reaction flask from ATTM dissolved in the cell medium. Staining with dichlorodihydrofluorescein diacetate or rhodamine 123 followed by photofluorography was conducted for the observation of reactive oxygen species (ROS) and mitochondrial membrane potential (ΔΨm) levels, respectively. Cell viability and release of lactate dehydrogenase (LDH) from the cells were measured with commercial kits. RESULTS: Similar to another H2S donor GYY4137, ATTM had an ability to release H2S in the cell medium in a dose-dependent manner. Treatment of human skin HaCaT cells with ATTM at concentrations of 25~400 μmol/L didn't significantly alter cell viability. Exposure of the cells to ultraviolet rays or a ROS donor H2O2 increased the intracellular ROS levels. Treatment with 400 μmol/L H2O2 significantly reduced the viability of HaCaT cells (P<0.01). However, before the treatment with H2O2, pretreatment with ATTM at 100 and 200 μmol/L markedly prevented the H2O2-induced cell injury (P<0.01). In addition, the treatment with H2O2 triggered ΔΨm loss (P<0.01) and LDH release from the cells (P<0.01). Prior to suffering from H2O2 injury, the preconditioning with 200 μmol/L ATTM significantly improved ΔΨm levels (P<0.05) and attenuated LDH release from the cells (P<0.01).CONCLUSION: ATTM is capable of releasing H2S and protecting human skin cells against oxidative injury.  相似文献   

5.
AIM: To investigate whether oxidative stress is able to induce autophagy in mesenchymal stem cells (MSCs), and to explore the effects of autophagy on MSC proliferation and apoptosis under oxidative stress circumstance as well as the underlying mechanism for promoting the therapeutic effects of transplanted MSCs on treating diabetes mellitus erectile dysfunction (DMED). METHODS: Hydrogen peroxide (H2O2) was applied to simulate the oxidative stress circumstance. The effects of H2O2 at concentration of 0, 50, 100, 200, 400 μmol/L on the viability of MSCs were tested by the method of Trypan blue exclusion and MTT assay respectively . The methods of MTT assay, Western blot and transmission electron microscope (TEM) were used to explore the effects of H2O2 on MSC apoptosis and autophagy. RESULTS: The proliferation of MSCs was obviously inhibited by H2O2 in a dose-dependent manner (P<0.01) and the 50% inhibiting concentration (IC50) was (384.58±16.89) μmol/L. H2O2 induced apoptosis and autophay of MSCs. The proliferation rate of MSCs was suppressed by H2O2 significantly (P<0.05), with a further decline by blockade of autophagy (P<0.05) whereas increased by blockade of apoptosis (P<0.05). H2O2 induced MSCs apoptosis obviously (P<0.05), with an augment of apoptosis (P<0.05) by blockade of autophagy. Furthermore, the H2O2 increased expression of cleaved caspase-3 and cleavage of poly ADP-ribose polymerase 1 (PARP1), Which were decreased by apoptosis blockade whereas were enhanced by blockade of autopahgy. CONCLUSION: Oxidative stress plays a dual role in MSC survival, which induces MSC apoptosis and autophagy. Moreover, blockade of autophagy intensifies MSC apoptosis. Therefore, it is a promising method to ameliorate the effects of stem-cell based therapy on DMED by enhancing protective autophagy to increase the survival rate of transplanted MSCs against oxidative stress circumstance caused by diabetes mellitus.  相似文献   

6.
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.  相似文献   

7.
AIM: To evaluate the effect of senegenin (Sen) on H2O2-treated retinal ganglion cells (RGCs) and to explore its underlying mechanisms. METHODS: RGCs were retrograde labeled by injection of fluorogold into the superior colliculi of SD rats on the postnatal day 3. On the postnatal days 6 to 8, the retinas were dissociated with papain and cultured. Primary RGCs cultured in vitro were treated with H2O2 and/or various doses of Sen. The viability of RGCs was evaluated by counting the fluorescence-labeled neurons under microscope. The morphological changes of the nuclei in the retinal neurons were observed by Hoechst 33258 staining. Western blotting was applied to determine the expression of cleaved caspase-3, cytochrome C and Bcl-2 in cultured retinal neurons. RESULTS: Compared with the control cells, Sen at doses of 10, 20 or 40 μmol/L had no toxicity to RGCs (P>0.05). However, Sen at doses of 80 and 160 μmol/L had significant toxicity to RGCs (P<0.01). Compared with H2O2-injured group, Sen at doses of 10, 20 and 40 μmol/L effectively protected against H2O2-induced injury in RGCs (P<0.05) with the best efficiency at 40 μmol/L. Hoechst 33258 staining showed that the neuronal apoptosis caused by H2O2 was reduced by Sen. The results of Western blotting showed an up-regulation of Bcl-2, and decreased cytochrome C and cleaved caspase-3 levels by Sen in H2O2-treated retinal neurons. CONCLUSION: Sen is able to protect RGCs from H2O2-induced injury by enhancing Bcl-2 expression and inhibiting cell apoptosis.  相似文献   

8.
AIM: To investigate the effect of acetyl-L-carnitine (ALC) on H2O2-induced oxidative damage in PC12 cells and its possible mechanism. METHODS: A moderate oxidative damage PC12 cell model was induced by exposure of the PC12 cells to H2O2. ALC at different concentrations (100, 200 and 400 μmol/L) was applied to the PC12 cells cultured in vitro, and CCK8 assay was used to detect the cell viability. The cells were divided into control group, H2O2 group, and low-ALC, medium-ALC and high-ALC groups. The apoptosis of the cells was analyzed by flow cytometry. The protein levels of Nrf2 and cleaved caspase-3 were determined by Western blot. The nuclear translocation of Nrf2 was observed by immunofluorescence staining. RESULTS: ALC at different concentrations (100, 200 and 400 μmol/L) significantly inhibited H2O2-induced PC12 cell apoptosis, and the medium concentration group had the best effect. Compared with H2O2 group, low, medium and high concentrations of ALC significantly increased the viability of the PC12 cells induced by H2O2, inhibit cell apoptosis (P<0.05), significantly down-regulated the protein level of cleaved caspase-3 (P<0.05), up-regulated the protein level of Nrf2 (P<0.05), and promoted the translocation of Nrf2 from the cytoplasm to the nucleus. CONCLUSION: Acetyl-L-carnitine attenuates H2O2-induced oxidative damage of PC12 cells, inhibits the apoptosis and increases the viability, which is related to the activation of Nrf2 signaling pathway.  相似文献   

9.
AIM: To study the effect of Lycium barbarum polysaccharides (LBP) on oxidative stress injury of human endothelium-like EA.hy926 cells induced by hydrogen peroxide (H2O2). METHODS: The EA.hy926 cell model of oxidative stress injury was established by H2O2 treatment. The EA.hy926 cells were divided into 5 groups:control group, damage (H2O2 at 50 mmol/L) group, LBP (100 mg/L) group, anti-damage groups (LBP at 50 mg/L, 100 mg/L or 200 mg/L+50 mol/L H2O2), and LY294002 (20 μmol/L) group. The effect of LBP at different concentrations on the cell viability of EA.hy926 cells was measured by CCK-8 assay, and the optimum concentration of LBP was screened out. The apoptotic of EA.hy926 cells was analyzed by flow cytometry. Acridine orange/ethidium bromide (AO/EB) staining was used to observe the morphological characteristics of the apoptotic cells. The cell migration ability was detected by scratch method. The levels of nitric oxide (NO) and vascular endothelial growth factor (VEGF) in the cell culture medium were examined. The protein levels of cleaved caspase-3, Bax, Bcl-2, endothelial NO synthase (eNOS), p-eNOS and p-Akt were determined by Western blot. RESULTS: LBP at concentration of 100 mg/L significantly attenuated the injury of EA.hy926 cells induced by H2O2, as indicated by improved cell viability (P<0.05) and decreased apoptosis (P<0.05). Pretreatment with LBP elevated the levels of NO and VEGF (P<0.05), and promoted the migration ability of EA.hy926 cells. LBP also increased the Bcl-2/Bax ratio, down-regulated the protein level of cleaved caspase-3, and up-regulated the protein levels of eNOS and p-eNOS. The protective effect of LBP were abolished by pretreatment of the EA.hy926 cells with the inhibitor of PI3K (P<0.05). As a result, the protein level of p-Akt was down-regulated, and the level of NO was also significantly reduced. CONCLUSION: LBP has protective effect on H2O2 -induced EA.hy926 cells by attenuating apoptosis of the cells. The mechanism is closely related to the activation of PI3K/Akt/eNOS signaling pathway.  相似文献   

10.
AIM: To investigate the protective effect of hypoxic preconditioning on human bone marrow mesenchymal stem cells (hBM-MSCs), and to provide basic experimental support for more effective autologous stem cell transplantation in aged patients. METHODS: The old hBM-MSCs were subjected to hypoxic preconditioning using a hypoxia incubator chamber for 24 h. The cells were divided into young group, old group and old+hypoxia group (with 24 h hypoxic preconditioning). Hydrogen peroxide (H2O2, 300 μmol/L) was applied to simulate the oxidative stress. The cells were treated with 50 μmol/L LY294002 for 2 h to inhibit PI3K/AKT pathway. BrdU incorporation and CCK-8 assay were used for analyzing the cell proliferation and viability. The protein levels of Bax, Bcl-2 and p-AKT were measured by Western blot. RESULTS: BrdU-positive cells, which represented the cell proliferation, and the cell viability were significantly increased in old+hypoxia group compared with old group (P<0.05). The protein level of Bax decreased (P<0.05) and Bcl-2 increased (P<0.05) in old+hypoxia group compared with old group after using 300 μmol/L H2O2 simulate. the oxidative stress. The phosphorylation of AKT was enhanced by hypoxic preconditioning in old group (P<0.05). The protective effect of hypoxic preconditioning on the cell survival was decreased after treated with LY294002 (inhibitor of the PI3K/AKT pathway) (P<0.05). CONCLUSION: Hypoxic preconditioning increases the survival and proliferation of old hBM-MSCs by activation of AKT pathway.  相似文献   

11.
AIM: To investigate the effects of mollugin on the viability and collagen synthesis of rat hepatic stellate cell line CFSC-2G. METHODS: The activation of CFSC-2G cells was induced with low concentration (10 μmol/L) of hydrogen peroxide (H2O2) for 30 min in the experiment. The viability of the CFSC-2G cells after exposed to mollugin at different concentrations (0, 20, 40, 60 and 120 μmol/L) was detected by MTT assay. The mRNA and protein expression levels of nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), nuclear factor-κB (NF-κB) p65, Bcl-2, Bcl-xL, Bax, and hepatic stellate cell activation markers α-smooth muscle actin (α-SMA) and collagen type I (Col Ⅰ) were detected by real-time PCR and Western blot. The phosphorylation level of p38 mitogen-activated protein kinase (p38 MAPK) was determined by Western blot. RESULTS: Mollugin significantly inhibited the viability and collagen synthesis of activated CSFC-2G cells induced by H2O2. The expression of Nrf2, HO-1 and Bax at mRNA and protein levels, and the phosphorylation level of p38 MAPK were promoted, while the levels of NF-κB p65, Bcl-2, Bcl-xL, α-SMA and ColⅠwere inhibited by mollugin (P<0.05). CONCLUSION: Mollugin may inhibit H2O2-induced viability and collagen synthesis of the CSFC-2G cells by activating Nrf2 and HO-1, and blocking the NF-κB p65 and Bcl-2 expression.  相似文献   

12.
AIM: To investigate the effect of ecdysterone (EDS) on H9c2 cardiomyocytes after oxidative stress. METHODS: H9c2 cells were cultured in vitro and divided into control group, high dose (2 μmol/L) of EDS group, middle dose (1.5 μmol/L) of EDS group, low dose (1 μmol/L) of EDS group, and H2O2 group. H9c2 cardiomyocytes in H2O2 group and high, middle and low doses of EDS groups were exposed to H2O2 for 6 h to establish the model of oxidative stress. The viability of the H9c2 cells was detected by CCK-8 assay. The apoptosis of H9c2 cells was analyzed by flow cytometry. The levels of lactate dehydogenase (LDH) and creatine kinase-MB (CK-MB) in the culture medium, and the levels of superoxide dismutase (SOD) and malondialdehyde (MDA) in the H9c2 cells were measured by colorimetry. The generation of reactive oxygen species (ROS) and the mitochondrial membrane potential were evaluated by flow cytometry and confocal laser scanning microscopy. The protein levels of Bax, Bcl-2 and cleaved caspase-3 in the H9c2 cells were determined by Western blot. RESULTS: Ecdysterone at the selected concentrations had no effect on the viability of H9c2 cells. Compared with control group, the levels of LDH, CK-MB, ROS and MDA, and the apoptotic rates of the H9c2 cells were significantly increased after treated with H2O2, but were decreased by EDS treatment in a dose-dependent manner. The levels of SOD and mitochondrial membrane potential of the H9c2 cells in H2O2 group were reduced significantly compared with control group, but high, middle and low doses of EDS treatments up-regulated the levels of SOD and mitochondrial membrane potential in H2O2-treated H9c2 cells. The protein levels of Bax and cleaved caspase-3 in the H9c2 cells in H2O2 group showed significant elevation in comparison with control group, and the protein expression of Bcl-2 declined in H2O2 group compared with control group, but high, middle and low doses of ecdysterone treatments down-regulated the protein levels of Bax, cleaved caspase-3 and up-regulated the expression of Bcl-2 in H2O2-treated H9c2 cells. CONCLUSION: Ecdysterone attenuates the effect of H2O2-induced oxidative stress on H9c2 cardiomyocytes. The mechanism may be involved in scavenging oxidative stress products, increasing antioxidant enzyme activity and improving mitochondrial function.  相似文献   

13.
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14.
AIM: To study the effect of 6-gingerol on the apoptosis of rat nucleus pulposus cells and its possible mechanism. METHODS: Rat nucleus pulposus cells were isolated and cultured. The effects of 6-gingerol and hydrogen peroxide (H2O2) at different concentrations on the viability of nucleus pulposus cells were measured by CCK-8 assay. After 6-gingerol treatment, the protein level of p-Akt was determined by Western blot. The cells were divided into 4 groups:control group, H2O2 group, 6-gingerol group (6-gingerol + H2O2) and LY294002 group (6-gingerol + H2O2 + LY294002). The apoptotic rate and the levels of reactive oxygen species (ROS) were analyzed by flow cytometry. TUNEL fluorescence staining was used to observe the number of apoptotic cells. The morphological changes of mitochondria were observed under transmission electron microscope, and Western blot was used to determine the protein levels of caspase-3, Bcl-2, Bax, p-Akt, Akt and p53. The mRNA expression of aggrecan and type II collagen was measured by RT-qPCR. RESULTS: The results of CCK-8 assay showed that the optimal concentration of 6-gingerol for promoting the viability of rat nucleus pulposus cells was 24 mg/L, and the exposure condition of H2O2 at 80 μmol/L for 6 h was appropriate for establi-shing the cell damage model. 6-Gingerol increased the protein level of p-Akt in a time-dependent manner. The apoptotic rate, ROS level and TUNEL positive cells in H2O2 group were significantly increased compared with control group. The mitochondrial edema was obvious in H2O2 group compared with control group. The protein levels of pro-apoptotic molecules caspase-3, Bax and p53 were significantly increased, while anti-apoptotic protein Bcl-2, and mRNA expression of aggrecan and type II collagen were significantly decreased compared with control group (P<0.05). 6-Gingerol exerted a protective effect against H2O2-induced apoptosis and promoted the expression of anti-apoptotic proteins. However, this effect was weakened after treatment with PI3K/Akt signaling pathway inhibitor LY294002. CONCLUSION: H2O2 induces damage and dysfunction of rat nucleus pulposus cells, and 6-gingerol may inhibit H2O2-induced apoptosis of nucleus pulposus cells by activation of PI3K/Akt signaling pathway.  相似文献   

15.
AIM: To observe the effect of docosahexaenoic acid(DHA) on H2O2-induced apoptosis in human retinal pigment epithelium cells and its molecular mechanism. METHODS: Human retinal pigment epithelium cell line ARPE-19 was cultured in vitro, and 12.5 mmol/L H2O2 was used to mimic the oxidative stress condition. The cells were treated with 30~100μmol/L DHA for 4~24 h. The expression of heme oxygenase-1(HO-1) at mRNA and protein levels was detected by real-time PCR and Western blot, respectively. The enzymic activity of HO-1 was measured by colorimetry. Production of reactive oxygen species(ROS) was determined by fluorescent probe. Activation of NF-E2-related factor 2(Nrf2) was examined by immunofluorescence method. Apoptosis of ARPE-19 cells was analyzed by flow cytometry. RESULTS: The mRNA and protein expression and the enzymic activity of HO-1 were significantly increased in the ARPE-19 cells after DHA treatment. Meanwhile, nuclear translocation of Nrf2 was also observed. Apoptosis appeared and ROS was produced upon H2O2 incubation. In contrast, DHA at 100μmol/L significantly abrogated H2O2-induced apoptosis and ROS production. Furthermore, silencing of HO-1 by specific siRNA, or treatment with ZnPP, an inhibitor of HO-1, partly counteracted the protective effect against H2O2-induced apoptosis and ROS production. CONCLUSION: DHA protects retinal pigment epithelial cells against oxidative stress via induction of heme oxygenase-1 expression after Nrf2 activation.  相似文献   

16.
AIM: To observe the expression of 26S proteasome LMP2 subunit in vascular endothelial cells (VECs) under oxidative stress, and to evaluate its role in the development of tolerance against oxidative stress in VECs. METHODS: The cell model of H2O2 preconditioning-induced oxidative tolerance was established in VECs. The expression of LMP2 was detected by cellular immunofluorescent labeling and Western blotting. The LMP2 anti-sense and sense oligonucleotides were transfected into VECs by LipofectamineTM 2000. The damages of VECs were evaluated by detecting the activity of lactate dehydrogenase (LDH) and the concentration of malondialdehyde (MDA) in the culture medium. RESULTS: H2O2 (500 μmol/L for 3 h) induced oxidative stress in VECss in a dose- and the activity of time-dependent manner, characterized by the increase in the concentration of MDA and LDH in the culture medium. Pretreatment with H2O2 (10 μmol/L for 24 h) up-regulated the expression of LMP2. Meanwhile, the capacity of cellular tolerance against oxidative stress induced by H2O2 was increased as the concentration of MDA and the activity of LDH in the culture medium significantly decreased. Compared with H2O2 group, up-regulation of LMP2 by IFN-γ pretreatment (20 μg/L for 48 h) increased the tolerance of VECs against H2O2 injury, and the MDA conentration and the activity of LDH in the culture medium also significantly decreased. Transfection with LMP2 antisense oligonucleotide partly inhibited the increased expression of LMP2 induced by IFN-γ in VECs and abolished the tolerance against H2O2. CONCLUSION: The 26S proteasome LMP2 subunit is associated with the development of the tolerance against H2O2-induced oxidative stress in VECs.  相似文献   

17.
AIM: To investigate the effects of Schisandrin B (Sch B) on apoptosis of lens epithelial cells (LEC) treated with H2O2. METHODS: Eyes in SDrats were excised and lenses were separated under operating microscope in sterilized condition. Lenses were divided randomly into four groups with different treatment: control group, hydrogen peroxide group (H2O2), pirenoxine sodium group (PS) and schisandrin Bgroup (Sch B). Lenses were incubated in CO2 incubator for 24 h with 300 μmol·L-1 H2O2 and with or without 0.5 mmol·L-1 Sch B. LECaoptosis and apoptosis rate were measured by TUNELmethod. Ultrastructure changes and apoptosis bodies of LECwere observed via transmitted electron microscope. RESULTS: (1) Apoptosis rate in H2O2 group (92.0±2.6) was significantly higher than that in control group (3.5±1.8). Apoptosis rate in Sch Bgroup (13.8±3.27) was remarkably lower than that in H2O2 group and PSgroup. (2) Ultrastructure observation indicated that apoptosis cells occurred in most LEC in H2O2 group and the changes were severe presenting different stages. While a few apoptosis cells were observed in Sch Bgroup, the changes were slight and most of them were in early and middle stages. CONCLUSION: These data indicated that Sch Bsignificantly inhibited apoptosis of LECduring experimental oxidative injury, the effects were stronger than PS.  相似文献   

18.
AIM: To study the protective effect of piperine on abnormalityies of inward rectifier potassium current (IK1) and ultra rapid delayed rectifier potassium current (IKUr) induced by hydrogen peroxide (H2O2) in single rabbit atrial myocytes. METHODS: The technique of whole-cell patch-clamp was used to study the effect of H2O2 at concentration of 50 μmol/L on IK1 and IKUr in single rabbit atrial myocytes. The protective effect of pretreatment with piperine (7 μmol/L) was also observed. RESULTS: The piperine at concentration of 7 μmol/L had no significant effect on IK1 and IKUr and their channel dynamics. In the presence of H2O2 at concentration of 50 μmol/L, the peak currents of IK1 and IKUr reduced significantly (P<0.05).The steady-state activation curve of IKUr was shifted right, the steady-state inactivation curve of IKUr was shifted left, and the recovery from inactivation of IKUr was shifted downward. The IKUr showed frequency-dependent characteristics. Piperine at concentration of 7 μmol/L significantly alleviated the inhibitory effect of H2O2 on IK1 and IKUr (P<0.01). In addition, piperine protected against the changes of IKUr dynamics induced by H2O2. CONCLUSION: Piperine alleviates the abnormalities of IK1 and IKUr induced by oxidative stress in atrial myocytes.  相似文献   

19.
AIM: To observe the influence of erythropoietin (EPO) on eryptosis and production of reactive oxygen species (ROS) in erythrocytes under stimulation of hydrogen peroxide (H2O2),and to explore its related mechanism. METHODS: The erythrocyte suspension (1%) was cultured in vitro and divided into 3 groups:control group (C group, the culture medium was PBS), H2O2 group (H group, the culture medium was PBS containing H2O2 at final concentration of 100 μmol/L) and EPO group (E group, the culture medium was PBS containing H2O2 at final concentration of 100 μmol/L and EPO at final concentration of 2×104 U/L). The erythrocytes were collected at 24 h and 60 h. The eryptosis was detected by flow cytometry with Annexin V staining. The production of ROS and intracellular calcium ion concentration ([Ca2+]i) were also analyzed by flow cytometry. RESULTS: The eryptosis in C group was increased as the incubating time extended. The eryptosis in H group was higher than that in C group (P<0.01), while that in E group was lower than that in H group (P<0.01). Meanwhile, ROS production and[Ca2+]i were higher in H group than those in C group (P<0.01), but those were lower in E group than those in H group (P<0.05 or P<0.01). CONCLUSION: EPO inhibits eryptosis induced by H2O2 and its mechanism may be related to antioxidant effect and change of[Ca2+]i.  相似文献   

20.
AIM: To observe the effect of rapamycin on the apoptosis of mouse astrocytes in vitro.ME-THODS:The astrocytes from C57BL/6J newborn mouse pups were isolated and primarily cultured. The effect of rapamycin on the viability of astrocytes was assessed by MTT assay. The mean fluorescence intensity of SYTOX® Green stain in the astrocytes was detected by fluorescence microplate reader in order to analyze the effects of rapamycin on the cell death induced by H2O2, ionomycin and/or deferorxamin. DiOC6(3) staining was used to analyze the mitochondrial membrane potential of the astrocytes induced by H2O2. Flow cytometry analysis was used to determine the production of ROS in the astrocytes and mitochondria by staining with H2DCFDA and MitoSOXTM Red reagent, respectively.RESULTS: Rapamycin at concentration of 0.5 μmol/L protected the astrocytes against cell death induced by H2O2 or deferoxamine plus ionomycin. Rapamycin protected the mitochondrial membrane potential of astrocytes from the injury of H2O2. It also reduced the production of ROS in the astrocytes and decreased the level of ROS in the mitochondria.CONCLUSION: Rapamycin reduces the ROS overload in the mitochondria, keeps mitochondrial membrane potential safety and protects the astrocytes against apoptosis in vitro.  相似文献   

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