| Summary: | 碩士 === 國防醫學院 === 海底醫學研究所 === 95 === Methamphetamine (MA) is an abused drug that may cause psychiatric and neurotoxic damage in humans. Nevertheless, the molecular basis of the mechanism underlying these MA-induced neurotoxic effects remains to be clarified. MA-induced cell damage is associated with the formation of toxic reactive oxygen species (ROS) and cause activation of both caspase dependent and independent pathway. MA causes increase in pro-death (BAX, BAD and BID) but decrease in anti-apoptotic Bcl-2 related protein (Bcl-2 and Bcl-XL). These proteins are known to be involved in neither activating or inhibiting the mitochondria-dependent cell death pathway. G-CSF (Granulocyte colony-stimulating factor) is a hematopoietic growth factor that has been used for many years in clinical practice to treatment neutropenia by chemotherapy. Recently, this factor has been shown to exhibit neuroprotective effects in human ischemic stroke and rat ischemic brain. G-CSF has found that plays a neuroprotetive role on MPTP-induced dopamine neuron loss. In this study, we investigated the neuroprotective effects and signal mechanisms of G-CSF on MA-induced apoptosis of primary cortical cells.
In the methods, we used flowcytometry to detect the free radical production, mitochondrial membrane potential dysfunction and apotosis. The immunocytochemitry and MTT test are to observe the change of neuron and microglia morphology and cell survival. The ERK, PI3K and Bcl-2 inhibitors were used to examine which pathway was involved in G-CSF neuroprotective role.
According to our findings, pretreatment with G-CSF were found to reduce MA-induced ROS production, and neuronal apoptosis, and restore mitochondrial membrane potential in primary cortical culture. However, G-CSF can reduce MA-induced neurotoxicity but can not alter the MA-induced activation of microglia. Inhibition of ERK abrogated G-CSF protection on cell apoptosis and mitochondrial dysfunction induced by MA, but no effect on ROS production of MA. Therefore, inhibition of PI3K or Bcl-2 significantly blocked G-CSF effect in preventing cell apoptosis, ROS release and mitochondrial dysfunction induced by MA.
In conclusion, in the primary cortical cells, MA induced mitochondria-dependent neuronal toxicity, including free radical production, mitochondrial membrane potential dysfunction and apoptosis. G-CSF plays a neuroprotective role on MA-induced neurotoxicity, and ERK, PI3K and Bcl-2 pathways were involved in the neuroprotective effect of G-CSF. Thus, G-CSF may be a new therapeutic strategy for neurotoxin-induced damage.
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