Preliminary Research Of Protective Effects Of Ketamine On Cerebral Ischemic Injury Of Primary Cultured Neurons From Embryonic Rat Brain

Objects: Using an ischemic model of primary cultured rat embryo cerebral neuron in vitro to study the cellular and molecular mechanism of ketamine on neuron ischemic injury. Methods: The mixed cell culture riching in neuron were deprived both oxygen and glucose using common incubator and home-made tightly closed container. The LDH, NSE, NO and glutamate concertration of supernatant culture medium were measured at different time before and after anoxia. Using biochemical assay, NSE ELISA, fluoroscope, HPLC and RT-PCR methods to study the changes of lactate dehydrogenase(LDH), neuro-specific enolase(NSE), nitric oxide(NO), glutamate concertrations and the expression of NSE of anoxia neurons and neurons pretreated with different concentrations of ketamine. Rsults: One hour of oxygen-glucose deprivation was associated with a large increase in extracellular LDH (P<0.05). Although the three or five-hours groups had also increased significantly (P<0.01) compared with control group, but there's no differences among these three groups (P>0.05). One hour of oxygen-glucose deprivation was associated with a large increase in extracellular NSE, NO, glutamate concertration (P<0.01) and a large decrease in intracellular NSE concertration (P<0.01), The three or five-hours groups had also increased significantly (P<0.01), and there was significant difference compared with one-hours group (PO.01). As for the one-hour oxygen-gluose deprivation group, the extracellular concentrationof NO and NSE decreased, the intracellular concentration NSE increased significantly with the increase of pretreated concentration of ketamine. Until the maximum concentration of ketamine (100imol/L), all of these indexs went back to close to normal level. As for the five-hours oxygen-gluose deprivation group, the extracellular concentration of LDH and glutamate decreased significantly with the increase of pretreated concentration of ketamine. Immediately after slight anoxia for half-hours, the expression of NSE increased significantly (P<0.01). After pretreated with different concentrations of ketamine, the value of each group went down. All of these had significantly defferences with control group (P<0.01). Conclusion: These observations suggest that ketamine play a partial protective role on neuron ischemic injury which may be related to the non-competitive antagonistic effect of NMD A receptor, inhibition of excitatory amino acids, reduce the release of NO, the stabilization of plasma membrane permeability and regulation of some protective factors expression.