Imipramine protects retinal ganglion cells from oxidative stress through the tyrosine kinase receptor B signaling pathway

Retinal ganglion cell（RGC） degeneration is irreversible in glaucoma and tyrosine kinase receptor B（Trk B）-associated signaling pathways have been implicated in the process.In this study,we attempted to examine whether imipramine,a tricyclic antidepressant,may protect hydrogen peroxide（H_2O_2）-induced RGC degeneration through the activation of the Trk B pathway in RGC-5 cell lines.RGC-5 cell lines were pre-treated with imipramine 30 minutes before exposure to H_2O_2.Western blot assay showed that in H_2O_2-damaged RGC-5 cells,imipramine activated Trk B pathways through extracellular signal-regulated protein kinase/Trk B phosphorylation.TUNEL staining assay also demonstrated that imipramine ameliorated H_2O_2-induced apoptosis in RGC-5 cells.Finally,Trk B-Ig G intervention was able to reverse the protective effect of imipramine on H_2O_2-induced RGC-5 apoptosis.Imipramine therefore protects RGCs from oxidative stress-induced apoptosis through the Trk B signaling pathway.

Protective Effect of Reduced Glutathione C_(60) Derivative against Hydrogen Peroxide-induced Apoptosis in HEK 293T Cells

Hydrogen peroxide（H_2O_2） and free radicals cause oxidative stress, which induces cellular injuries, metabolic dysfunction, and even cell death in various clinical abnormalities. Fullerene（C_（60）） is critical for scavenging oxygen free radicals originated from cell metabolism, and reduced glutathione（GSH） is another important endogenous antioxidant. In this study, a novel water-soluble reduced glutathione fullerene derivative（C_（60）-GSH） was successfully synthesized, and its beneficial roles in protecting against H_2O_2-induced oxidative stress and apoptosis in cultured HEK 293 T cells were investigated. Fourier Transform infrared spectroscopy and 1H nuclear magnetic resonance were used to confirm the chemical structure of C_（60）-GSH. Our results demonstrated that C_（60）-GSH prevented the reactive oxygen species（ROS）-mediated cell damage. Additionally, C_（60）-GSH pretreatment significantly attenuated H_2O_2-induced superoxide dismutase（SOD） consumption and malondialdehyde（MDA） elevation. Furthermore, C_（60）-GSH inhibited intracellular calcium mobilization, and subsequent cell apoptosis via bcl-2/bax-caspase-3 signaling pathway induced by H_2O_2 stimulation in HEK 293 T cells. Importantly, these protective effects of C_（60）-GSH were superior to those of GSH. In conclusion, these results suggested that C_（60）-GSH has potential to protect against H_2O_2-induced cell apoptosis by scavenging free radicals and maintaining intracellular calcium homeostasis without evident toxicity.

The Effects and Mechanism of GSA on Expression of MCP-1 in Cultured Human Umbilical Vein Endothelial Cells

Objectives To investigate the effects and mechanism of glycated serum albumin(GSA) on expression of Monocyte chemoattratant protein-1(MCP-1) in Endothelial Cells. Methods Human Umbilical Vein Endothelial Cells (HUVEC)are cultured with GSA of different concentrations and interfered by glycosylation products inhibitor Aminoguanidine (AG) and anti-oxidant N-acetylcy-steine (NAC), The expression of MCP-1 are evaluated by Immunocytochemistry and Sandwich ELISA. MDA content and SOD activity are determined by the technique of TBA and XOD respectively. Results GSA can stimulate MCP-1 production and secretion. Immunocytochemistry showed that after HUVECs were cultured with 50 mg/L GSA, expression of MCP-1 in group 4hrs, 8hrs and 12hrs was 1.3, 1.9 and 2.8 fold as much as that in control group (P < 0.01), and there was significant difference among the experiment groups(P < 0.01). Sandwich ELISA showed that expression of MCP-1 in three different groups was 1.6, 2.4 and 3.0 fold as much as that in control group(P < 0.01), and there was significant difference among the experiment groups(P < 0.01); GSA can cause the decrease of SOD activity(P < 0.05) and increase of MDA content(P < 0.01); AG and NAC can restrain obviously the expression of MCP-1 of HUVECs stimulated by GSA(P < 0.01); NAC can restrain the effect of GSA on SOD activity and MDA content in HUVECs (P < 0.05). Conclusions GSA can stimulate the expression of MCP-1 of endothelial cells by inducing endothelial cells oxidative stress.

Protection of Salidroside on Primary Astrocytes from Cell Death by Attenuating Oxidative Stress

Objective To investigate whether salidroside（SAL） has protective and anti-oxidative effects on astrocytes. Methods Firstly, SAL was extracted from the roots of Rhodiola rosea with 70% ethanol and butanol to obtain crude phenylethyl alcohol glycosides which have been known as bioactive part of R. rosea; Secondly, WST-1 assay was carried out to assess the cell viability of astrocytes and cortical neurons under the treatment of the purified（〉 95%） SAL. Moreover, WST-1 assay was also used to evaluate the cytoprotective effects of SAL preventing astrocytes from staurosporine-induced cell death; Thirdly, we examined the spontaneous reactive oxygen species（ROS） and staurosporine-induced ROS generation in astrocytes in the absence or presence of SAL.Results SAL was observed to improve the astrocytes viability but not cortical neurons. In addition, SAL was able to ameliorate staurosporine-induced cell death. Moreover, SAL was able to attenuate the spontaneous ROS and staurosporine-induced ROS generation. Conclusion We here confirm that the anti-oxidative effect of SAL on primary astrocytes might be an important mechanism accounting for the cytoprotective effects from SAL.

c-Abl-MST1 Signaling Pathway Mediates Oxidative Stress Induced Neuronal Cell Death

Oxidative stress influences cell survival and homeostasis, but the mechanisms underlying the biological effects of oxidative stress remain to be elucidated. We have defined that the

Effects of Single and Repeated Exposure to a 50-Hz 2-mT Electromagnetic Field on Primary Cultured Hippocampal Neurons

The prevalence of domestic and industrial electrical appliances has raised concerns about the health risk of extremely low-frequency magnetic fields（ELF-MFs）. At present, the effects of ELF-MFs on the central nervous system are still highly controversial, and few studies have investigated its effects on cultured neurons. Here, we evaluated the biological effects of different patterns of ELF-MF exposure on primary cultured hippocampal neurons in terms of viability, apoptosis, genomic instability,and oxidative stress. The results showed that repeated exposure to 50-Hz 2-mT ELF-MF for 8 h per day after different times in culture decreased the viability and increased the production of intracellular reactive oxidative species in hippocampal neurons. The mechanism was potentially related to the up-regulation of Nox2 expression.Moreover, none of the repeated exposure patterns had significant effects on DNA damage, apoptosis, or autophagy, which suggested that ELF-MF exposure has no severe biological consequences in cultured hippocampal neurons.