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AIM: To explore whether necroptosis contributes to the high glucose (HG)-induced damage in hu-man umbilical vein endothelial cells (HUVECs).METHODS: The protein levels of receptor-interacting protein 3 (RIP3) and cleaved caspase-3 were detected by Western blot.The intracellular levels of reactive oxygen species (ROS) were deter-mined by DCFH-DA staining followed by photofluorography.Mitochondrial membrane potential (MMP) was measured by rhodamine 123 staining followed by photofluorography.RESULTS: Treatment of HUVECs with HG at different concentra-tions (10, 20 and 40 mmol/L glucose) for 24 h gradually enhanced the expression levels of RIP3.Treatment of HUVECs with HG (40 mmol/L glucose) for different time (3 h, 6 h, 9 h, 12 h and 24 h) also up-regulated the expression levels of RIP3, peaking at 9 h.Pretreatment of HUVECs with 20 μmol/L Z-VAD-FMK (an inhibitor of caspase) for 30 min before exposure to HG enhanced the expression level of RIP3.Pretreatment of HUVECs with 100 μmol/L necrostatin-1 (an inhi-bitor of necroptosis) for 1 h before exposure to HG alleviated the HG-induced injuries, such as a decrease in cell viability, an increase in ROS generation and dissipation of MMP, but up-regulated the protein level of cleaved caspase-3.CON- CLUSION: Necroptosis mediates HG-induced injury in HUVECs.There is a negative interacting between necroptosis and apoptosis.
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AIM:To explore the roles of Akt ( also called protein kinase B ) and active caspase-3 in the leptin-mediated chronic morphine antinociceptive tolerance in rats .METHODS: A model of chronic morphine antinociceptive tolerance was established in the SD rats .The protein levels of spinal Akt and cleaved caspase-3 were tested by Western blotting.The technique of immunohistochemical staining was used to detect the immunoreactivity positive cells of phospho -rylated ( p)-Akt and cleaved caspase-3 in the spinal cord .Double staining of immunohistochemistry was used to examine the cellular location of the p-Akt and cleaved caspase-3 positive cells.RESULTS: The chronic intrathecal injection of morphine (15 μg) for 7 d markedly upregulated the spinal protein levels of p-Akt and cleaved caspase-3 in the rats.Thirty min before injection of morphine , intrathecal injection of leptin antagonist (3μg) for 7 d significantly attenuated the upreg-ulation of the protein levels of p-Akt and cleaved caspase-3 induced by chronic morphine treatment .The p-Akt was exclu-sively observed in the spinal neurons .The cleaved caspase-3 was only localized with the spinal astrocytes .Intrathecal injec-ting the inhibitors of leptin , Akt and caspase-3 ameliorated the chronic antinociceptive tolerance .CONCLUSION: The spinal Akt pathway and active caspase-3 are involved in the leptin-mediated chronic morphine antinociceptive tolerance in rats.
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[Objective] To explore the cytoprotecfion of hydrogen sulfide (H_2S) against cobalt chloride (CoCl_2)-induced apeptosis in PC12 cells and the underlying mechanisms. [Methods] CoCl_2 (a chemical hypoxia-mimetic agent) was used to establish the chemical hypoxia-induced PC12 cell injuries model. Sodium hydrosulfide (NaHS) was used as a H_2S donor. The viability of PC12 cells was measured by CCK-8 assay. The percentage of apeptotic cells was assessed by propidium iodide stain flow cytometry (FCM). The morphological change of apeptotic cells was tested by using the chromatin dye Hoechst 33258. The mitochondrial membrane potential (MMP) was analyzed by rhodamine 123 staining and photofluorography. The level of reactive oxygen species (ROS) in PC12 cells was measured by DCFH-DA staining and photofluorography. [Results] CoCl_2 induced a decrease in cell viability and an increase in percentage of apeptosis in PC12 cells along with dissipation of MMP as well as overproduction of ROS. When PC12 cells were treated with Naris 30 min before CoCl_2 treatment a decrease in viability of PC12 cells induced by 600 μmol/L CoCl_2 was concentration-dependently blocked by NaHs (100, 200, and 400 μmol/L). Pretreatment with NaHS at 200 and 400 μmol/L obviously reduced the apepetotic percentage of PC12 cells induced by 600 μmol/L CoCl_2 and inhibited the dissipation of MMP and overproduction of ROS. [Conclusion] H_2S protected PC12 cells against CoCl_2-induced apeptosis, which may be associated with the inhibition of H_2S on the dissipation of MMP and overproduction of ROS induced by CoCl_2.
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AIM To study the adaptive cytoprotection of H 2O 2 preconditioning against oxidative stress damage in PC12 cell and the relationships between brain derived neurotrophic factor (BDNF) and the adaptive cytoprotection of H 2O 2 preconditioning. METHODS The viability of PC12 cells was evaluated by MTT assay. Apoptosis was detected by PI stain flow cytometer. Expression of BDNF was analyzed by immuo flow cytometer. RESULTS After H 2O 2 preconditioning, the survival of PC12 cells exposure to H 2O 2 (20～60 ?mol?L -1 ) was increased and the apoptosis of PC12 cells induced by H 2O 2 (20 or 30 ?mol?L -1 ) was inhibited and the expression of BDNF in PC12 cells was enhanced. CONCLUSION H 2O 2 preconditioning is protective against the damage of PC12 cells induced by H 2O 2 and its mechanisms may involve up modulation of the expression of BDNF.
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AIM To study the expression of brain-derived neurotrophic factor (BDNF) in lymphocytes modified by BDNF gene and its effect on the proliferation and the H 2O 2-induced apoptosis of PC12 cells for the transfer of ex vivo therapeutic gene into central nervous system (CNS) tissue with atraumatic means. METHODS Recombined BDNF cDNA plasmid was transfected by LipofectAMINE into the packing cell line PA317 and G418-resistant clones with highest titer was selected. Rat lymphocytes were infected repeatedly with virus supernatant. The expression of BDNF in rat lymphocytes was assayed by FCM and immunohistochemistry. The proliferation of PC12 cells was evaluated by MTT assay. H 2O 2-induced apoptosis of PC12 cells was determined by PI stain flow cytometry. RESULTS BDNF expressed in rat lymphocytes genetically modified and the concentration of BDNF in the conditioned medium of engineered lymphocytes had a linear correlation with the proliferation of the PC12 cells. The supernatant of lymphocytes modified by BDNF gene decreased the apoptosis of PC12 cells induced by H 2O 2. CONCLUSION Rat lymphocytes genetically modified can express and secret active BDNF in vitro.
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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.