title: Protective effects of tetramethylpyrazine on rat retinal cell cultures.
abstract: The retinal degeneration characterized with death of retinal ganglion cells is a pathological hallmark and the final common pathway of various optic neuropathies. Thus, there is an urgent need for identifying potential therapeutic compounds for retinal protection. Tetramethylpyrazine has been suggested to be neuroprotective for central neurons by acting as an antioxidant and a calcium antagonist. In this study, we tested the effects of tetramethylpyrazine on the viability of both neuronal and non-neuronal cells in mixed rat retinal cell cultures during a long-term cultivation or following hydrogen peroxide treatments. Cellular and biochemical analyses demonstrated that 50 microM tetramethylpyrazine significantly preserved neuronal morphology and survival in retinal cell cultures following 4-week in vitro cultivation as well as lethal exposures to hydrogen peroxide (10 microM or 50 microM for 24h). Hydrogen peroxide treatments induced remarkable increases in lipid peroxidation and mitochondrial reactive oxygen species (ROS) generation paralleled by the loss of mitochondrial membrane potential, microtubule-associated protein-2 (MAP-2) in neuronal soma and rattin peptide in cultured cells. Addition of tetramethylpyrazine in the cultures efficiently attenuated the signs of oxidative stress and retained abundance of MAP-2 and rattin in association with cell survival. In addition, siRNA-mediated downregulation of MAP-2 or rattin significantly increased the vulnerability of retinal neurons or the number of degenerating cells in the cultures, respectively, whereas exogenous humanin peptide, an analog of rattin, promoted cell survival in cultures under hydrogen peroxide attacks. These results suggest that tetramethylpyrazine protect retinal cells through multiple pathways and might be a potential therapeutic candidate for retinal protection in certain optic neuropathies.
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou 510060, China.
authors.forename: Zhikuan
authors.initials: Z
authors.lastname: Yang
authors.forename: Qingjiong
authors.initials: Q
authors.lastname: Zhang
authors.forename: Jian
authors.initials: J
authors.lastname: Ge
authors.forename: Zhiqun
authors.initials: Z
authors.lastname: Tan
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D018920:Coculture Techniques; D006861:Hydrogen Peroxide / Q000633:toxicity; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D009410:Nerve Degeneration / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology; D009457:Neuroglia / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology* / Q000627:therapeutic use; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D011719:Pyrazines / Q000494:pharmacology* / Q000627:therapeutic use; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D012160:Retina / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D012162:Retinal Degeneration / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics
chemical_list: C489788:MAP2 protein, human; D008869:Microtubule-Associated Proteins; D018696:Neuroprotective Agents; D011506:Proteins; D011719:Pyrazines; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; C464672:rattin protein, rat; D006861:Hydrogen Peroxide; C017953:tetramethylpyrazine