| Research Abstract |
We have found the followings regarding the neuroprotective effects in this project.
1) Neuroprotective effects of microglial cells. We found that cerebrocortical primary neurons died by apoptosis by incubating cells with sodium nitroprusside (SNP), a nitric oxide (NO)-donor compound, By the use of this apoptosis model, we investigated the effect of microglial cells on neuronal survival. As a result, the NO-induced neuronal apoptosis was completely prevented by microglial cells that were cocultured with neurons. Since the neuronal apoptosis was also largely inhibited by microglial conditioned medium, microglia-derived anti-apoptotic factor may be a soluble-factor(s). Furthermore, the conditioned medium was effective when it was applied after exposure to NO. Among a variety of known cytokines and growth factors that are produced by microglial cells, only tumor necrosis factor a significantly rescued neurons against NO-induced damage. 2) Neuroprotective effects of astrocytes. We investigated to determine whether astrocytes could rescue primary cerebrocortical neurons from reactive oxygen species (ROS)-induced apoptosis. By adding SNP, 3-morpholinosydononimine (SIN-1) or mixture of FeSO4 and ascorbic acid, NO, superoxide anion or hydroxyl radicals were introduced into culture plates of neurons. When astrocytes were cocultured with neurons, ROS-induced neuronal death was completely prevented. However, meningeal fibroblasts could not rescue neurons. When neurons were cultured on astrocytes-derived extracellular matrix (ECM), neuronal apoptosis was mostly prevented. The astrocyte-derived ECM contained laminin and fibronectin, and purified laminin and fibronectin significantly protected neurons against oxidative stress.
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