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 whe...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.展开更多
Background Paraquat （PQ; 1,1＇-dimethyl-4,4＇-bipyridinium）, a widely used herbicide, has been repeatedly suggested as a potential etiologic factor for the development of Parkinson＇s disease （PD）, owing to its st...Background Paraquat （PQ; 1,1＇-dimethyl-4,4＇-bipyridinium）, a widely used herbicide, has been repeatedly suggested as a potential etiologic factor for the development of Parkinson＇s disease （PD）, owing to its structural similarity to the known dopaminergic neurotoxicant 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine （MPTP）. This study aimed to observe the influence of paraquat on nigrostriatal dopaminergic neurons in C57BL/6 mice. Methods A total of 24 male C57BL/6 mice were assigned randomly to 3 groups： control group （treated by saline）, PQ treated group, and MPTP treated group. Mice in PQ treated group were taken orally with PQ （10 mg/kg） daily for four months. Locomotor activity was measured. Level of dopamine （DA） and its metabolites levels in the striatum were measured by high-performance liquid chromatography with an electrochemical detector （HPLC-ECD）, and tyrosine hydroxylase （TH） positive neurons were detected by using immunohistochemistry. At the same time, the activities of superoxide dismutase （SOD） and glutathione peroxidase （GSH-PX）, and the content of malondialdehyde （MDA） in substantia nigra were measured by spectrophotometry, mRNA expression of dopamine transporter （DAT） in dopaminergic neurons of substantia nigra was also determined by reverse transcription （RT）-PCR technique. Results Locomotor activities were significantly impaired in the PQ treated group. Level of DA and its metabolites levels in the striatum were declined. The activities of SOD and GSH-PX were decreased, and the content of MDA was increased in PQ treated mice compared with that in control group. Numbers of TH positive neurons and the mRNA expression of DAT in substantia nigra of mice were also decreased after PQ taken orally for four months. Conclusions The present study suggests that chronic oral administration of PQ could trigger dopaminergic neuron degeneration. Oxidative stress could be involved in the pathogenic mechanism of PD induced by PQ.展开更多
文摘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.
文摘Background Paraquat （PQ; 1,1＇-dimethyl-4,4＇-bipyridinium）, a widely used herbicide, has been repeatedly suggested as a potential etiologic factor for the development of Parkinson＇s disease （PD）, owing to its structural similarity to the known dopaminergic neurotoxicant 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine （MPTP）. This study aimed to observe the influence of paraquat on nigrostriatal dopaminergic neurons in C57BL/6 mice. Methods A total of 24 male C57BL/6 mice were assigned randomly to 3 groups： control group （treated by saline）, PQ treated group, and MPTP treated group. Mice in PQ treated group were taken orally with PQ （10 mg/kg） daily for four months. Locomotor activity was measured. Level of dopamine （DA） and its metabolites levels in the striatum were measured by high-performance liquid chromatography with an electrochemical detector （HPLC-ECD）, and tyrosine hydroxylase （TH） positive neurons were detected by using immunohistochemistry. At the same time, the activities of superoxide dismutase （SOD） and glutathione peroxidase （GSH-PX）, and the content of malondialdehyde （MDA） in substantia nigra were measured by spectrophotometry, mRNA expression of dopamine transporter （DAT） in dopaminergic neurons of substantia nigra was also determined by reverse transcription （RT）-PCR technique. Results Locomotor activities were significantly impaired in the PQ treated group. Level of DA and its metabolites levels in the striatum were declined. The activities of SOD and GSH-PX were decreased, and the content of MDA was increased in PQ treated mice compared with that in control group. Numbers of TH positive neurons and the mRNA expression of DAT in substantia nigra of mice were also decreased after PQ taken orally for four months. Conclusions The present study suggests that chronic oral administration of PQ could trigger dopaminergic neuron degeneration. Oxidative stress could be involved in the pathogenic mechanism of PD induced by PQ.
