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Aim To explore the role of heat shock protein 90(Hsp90)in hydrogen sulfide-induced protection against PC12 cells injuries elicited by cobalt chloride(CoCl_2).Methods Hydrogen sulfide preconditioning against CoCl_2-induced injury model was set up in PC12 cells.Cell viability was tested by using cell counter kit-8.Morphological changes in apoptotic PC12 cells were detected by Hoechst 33258 staining and photofluorography.Apoptotic rate was evaluated by propidium iodide(PI)staining and flow cytometry(FCM).The expression of Hsp90 was evaluated by Western blot.Results Hsp90 expression was upregulated after treatment with 400 μmol·L~(-1) sodium hydrosulfide(a H_2S donor),peaking at 3 h,returning to the basal level at 24 h.Furthermore,H_2S preconditioning obviously enhanced the upregulation of Hsp90 expression induced by CoCl_2.H_2S preconditioning markedly protected PC12 cells against injuries induced by CoCl_2,increasing the viability of cells and decreasing the percentage of apoptotic cells.17-allylamino-17-demethoxygeldanamycin(17-AAG),an inhibitor of Hsp90,antagonized H_2S preconditioning-induced Hsp90 activation and the adaptive cytoprotection.Conclusion H_2S can protect PC12 cells against CoCl_2-induced injuries,and upregulating the expression of Hsp90 may be one of the mechanisms underlying cytoprotection induced by H_2S preconditioning.
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Aim To explore the effect of survivin in PC12 cells against injuries induced by cobalt chloride(CoCl_2).Methods PC12 cells were exposed to CoCl_2 at different doses in different time to set up the chemical hypoxia induced PC12 cells injuries model.Cell viability was tested by using cell counter kit-8.Dose-effect(200～1 000 μmol·L~(-1))and time-effect(0～48 h)relationship between hypoxia induced by CoCl_2 and the expression of survivin was evaluated by western blot.Results PC12 cells viability was inhibited significantly by CoCl_2 in a dose and time dependent manners;At the concentrations from 200 to 600 μmol·L~(-1) CoCl_2 for 24 h,survivin expression was upregulated in a dose dependent manner,peaking at 600 μmol·L~(-1) CoCl_2 treatment,exceeding this concentration of CoCl_2,with dose increasing,survivin expression decreased.At the dose of CoCl_2 up to 1 000 μmol·L~(-1),survivin did not express basically;Treatment with 600 μmol·L~(-1) CoCl_2 in different time,within the range of 0～36 h,the expression of survivin enhanced in time dependent manner.But with the extension of time,survivin expression was declining; 17-allylamino-17-demethoxygeldanamycin (2 μmol·L~(-1)),an inhibitor of Hsp90,not only decreased survivin overexpression but also obviously enhanced the injuries of PC12 cells induced by CoCl_2,which didn't damage PC12 cells alone.Conclusion Upregulation of survivin expression may be one of the endogenous defense mechanisms for PC12 cells against chemical hypoxia.
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Objective To estimate the influences of N-acetyl cysteine (NAC) on a chemical hypoxiamimetic agent CoCl2 induced-injury to, and expressions of inflammatory factors by, an immortal human skin keratinocyte line HaCaT. Methods HaCaT cells were treated with CoCl2 of 2000 μmol/L for 4 hours to set up a chemical hypoxia-induced cell model of skin injury. NAC of various concentrations ( 1000, 2000, 3000 μmol/L)was used to pretreat HaCaT cells for 2 hours prior to the establishment of cell model. After these treatments,cell viability was detected by cell counting kit 8 (CCK-8), the levels of interleukin 6 and 8 (IL-6 and -8) and tumor necrosis factor α (TNF-α) in culture supernatant by ELISA kits, mitochondrial membrane potential (MMP) by rhodamine 123 (Rh123) staining and photofluorography, intracellular reduced glutathione (GSH)content by glutathione detection kit. Results An obvious decline was observed in HaCaT cell viability after pretreatment with various concentrations of NAC for 2 hours. The treatment with CoCl2 of 2000 μmol/L for 4 hours induced an elevation in the supernatant levels of IL-6, IL-8 and TNF-α and a decrease in GSH content and MMP, while the pretreatment with NAC for 2 hours retarded the CoCl2-induced increase in IL-6 and IL-8 levels as well as decrease in GSH content and MMP. Conclusion The reactive oxygen species (ROS) scavenger NAC can protect against CoCl2-induced injury to and inflammatory reaction in HaCaT cells, which may be associated with a decrement in oxidative stress.
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AIM: To explore the roles of heat shock protein 90 (HSP90) in the blockage of hydrogen sulfide (H2S) against chemical hypoxia-mimetic agent (cobalt chloride, CoCl_2)-induced oxidative stress injuries in H9c2 cardiac cell. METHODS: H9c2 cells were treated with CoCl_2 to set up the chemical hypoxia-induced the model of cardiomyocyte injury. Sodium hydrosulfide (NaHS, a H2S donor) was added into medium for 30 min before CoCl_2 treatment. ATP content was detected by high performance liquid chromatogram (HPLC). Mitochondrial membrane potential (MMP) was measured by rhodamine123 (Rh123) staining and photofluorography. The activity of superoxide dismutase (SOD) was observed using a SOD kit. The expression of heme oxygenase-1 (HO-1) was evaluated by Western blotting. RESULTS: CoCl_2 at concentration of 600 μmol/L significantly reduced SOD activity, ATP level and MMP, and enhanced the expression of HO-1 in H9c2 cells. Pretreatment with 400 μmol/L NaHS dramatically inhibited the cytotoxicity induced by CoCl_2, increased SOD activity, ATP level and MMP, decreased HO-1 expression. 17-allylamino-17 demethoxygeldanamycine(17AAG), an inhibitor of HSP90, obviously blocked the inhibitory effect of H2S on the CoCl_2-induced cytotoxicity, reduced the levels of ATP and MMP, increased HO-1 expression. However, no significantly influence on SOD activity was observed. CONCLUSION: HSP90 may mediate the cardioprotection of H2S via inhibiting the oxidative stress induced by chemical hypoxia.
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AIM: To explore the role of extracellular signal-regulated kinases ERK1/2-STAT3 pathway in adaptive cytoprotection induced by H2O2 preconditioning in PC12 cells.METHODS: In PC12 cells,the experimental model of cytoprotection by H2O2 preconditioning against oxidative stress-induced injury was set up.The morphological changes in the apoptotic cells were observed by using of chromatin dye Hoechst 33258.The percent of apoptotic cells was determined by flow cytometry(FCM) with propidium iodide staining.The levels of p-ERK1/2 and p-STAT3 expression were detected by Western blotting assay.RESULTS: Preconditioning with H2O2 at concentration of 100 ?mol/L for 90 min obviously inhibited apoptosis induced by 300 ?mol/L H2O2,and both ERK1/2 and STAT3 were activated.UO126(10 ?mol/L,an inhibitor of ERK1/2) or AG-490(10?mol/L,an inhibitor of JAK2) significantly blocked the cytoprotection effect of H2O2 preconditioning.Moreover,UO126(10 ?mol/L) also markedly inhibited the up-regulation of p-STAT3 expression by H2O2 preconditioning.CONCLUSION: H2O2 preconditioning activates ERK1/2-STAT3 signal pathway,which may be one of the mechanisms underlying H2O2 preconditioning-induced cytoprotection.
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AIM To study the protective effect of curcumin (Cur) on PC12 cells damage induced by oxidative stress. METHODS Using H 2O 2-induced PC12 cells damage as the model of neuron damage induced by oxidative stress, the proliferation of PC12 cells was observed by 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide(MTT)assay, the apoptosis of PC12 cells was detected by propidium iodide stain flow cytometry (FCM), the mitochondrial membrane potential (△?m) was analyzed by rhodamine123 stain FCM and the level of reactive oxygen species (ROS) in PC12 cells was analyzed by dihydrohodamine123 stain FCM. RESULTS In the presence of Cur (20 and 40 ?mol?L -1), the inhibitory rates of PC12 cells induced by H 2O 2 from 25 to 400 ?mol?L -1 and the apoptosis of PC12 cell induced by 100 and 200 ?mol?L -1 H 2O 2 for 24 h were decreased. The level of △?m was decreased significantly in PC12 cells after 100 and 200 ?mol?L -1 H 2O 2 treatment for 24 h, however, those decreases were significantly ameliorated by Cur (20 and 40 ?mol?L -1) treatment. The level of ROS was significantly increased in PC12 cells exposed to H 2O 2 (100 and 200 ?mol?L -1) for 12 h, whereas 40 ?mol?L -1 of Cur prevented the rise induced by H 2O 2. CONCLUSIONS Cur has protective effect on PC12 cells damage induced by oxidative stress and the effect might be attributed to its removal of ROS and increase of △?m level.
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Aim To explore the effect of chemical hypoxia-mimetic agent,cobalt chloride(CoCl2)on inflammatory reaction in human keratinocytes(HaCat cells).Methods After HaCat cells were treated with CoCl2 at different concentrations to set up a chemical hypoxia-induced cell model of skin injury,cell viability,intracellular reactive oxygen species(ROS),mitochondrial membrane potential(MMP),the levels of both interleukin 6(IL-6)and interleukin 8(IL-8)as well as the expression of heme oxygenase-1(HO-1)were detected.Results The viability of HaCat cells was reduced by CoCl2 at the concentrations from 500 to 3 000 ?mol?L-1,and the higher CoCl2 doses,the lower cell viability was.CoCl2 induced oxidative stress reaction(increasing ROS production and decreasing MMP).CoCl2 induced inflammatory reaction,enhancing the release of IL-6 and IL-8.CoCl2 at concentrations from 1 000 to 3 000 ?mol?L-1 upregulated HO-1 expression in HaCat cells.Conclusion CoCl2 induces not only oxidative stress,but also inflammatory reaction,increasing the release of both IL-6 and IL-8,as well as HO-1 expression.