Abstract
The retina is the most metabolically active tissue in the human body and hypoxia-induced retinal ganglion cell (RGC) death has been implicated in glaucomatous optic neuropathy. The aim of this study is to determine whether muscarinic receptor agonist pilocarpine, a classic antiglaucoma drug, possesses neuroprotection against cobalt chloride (CoCl2)-mimetic hypoxia-induced apoptosis of rat retinal ganglion cells (RGC-5 cells) and its underlying mechanisms. Cell viability was determined by Cell Counting Kit-8 assay and apoptosis was examined by annexin V and mitochondrial membrane potential (MMP) assays. Expressions of hypoxia-induced factor-1α (HIF-1α), p53, and BNIP3 were investigated by quantitative real-time PCR and western blot analysis. After treatment of 200 μM CoCl2 for 24 h, RGC-5 cells showed a marked decrease of cell viability by approximately 30%, increased apoptosis rate and obvious decline in MMP, which could largely be reversed by the pretreatment of 1 μM pilocarpine mainly via the activation of muscarinic receptors. Meanwhile, pretreatment of 1 μM pilocarpine could significantly prevent CoCl2-induced HIF-1α translocation from cytoplasm to nucleus and down-regulate the expression of HIF-1α, p53, and BNIP3. These studies demonstrated that pilocarpine had effective protection against hypoxia-induced apoptosis in RGCs via muscarinic receptors and HIF-1α pathway. The findings suggest that HIF-1α pathway as a “master switch” may be used as a therapeutic target in the cholinergic treatment of glaucoma.
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Acknowledgments
This study was supported by the National Natural Science Foundation of China (No. 30472012, 30600269, 30700280 and 30701018), the Research Fund for the Doctoral Program of Higher Education of China (20060248067 and 200802480058).
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Xu Zhu and Wei Zhou contributed equally to this work.
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Zhu, X., Zhou, W., Cui, Y. et al. Pilocarpine Protects Cobalt Chloride-induced Apoptosis of RGC-5 Cells: Involvement of Muscarinic Receptors and HIF-1α Pathway. Cell Mol Neurobiol 30, 427–435 (2010). https://doi.org/10.1007/s10571-009-9467-2
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DOI: https://doi.org/10.1007/s10571-009-9467-2