Effects of isoflurane on oxygen-glucose deprivation-induced changes of gene expression profiling in glial-neuronal cocultures.

BACKGROUND

Isoflurane decreases ischemia-induced neuronal injury. The mechanisms of this effect are largely unknown. We hypothesize that isoflurane induces expression of protective stress genes and decreases expression of apoptosis-related genes.

METHODS

The mRNA expression of about 1300 genes related to neurobiology in rat glial-neuronal cocultures was evaluated by microarray technology. Four experimental conditions were examined: control; 2% isoflurane; oxygen-glucose deprivation (OGD, to simulate ischemia in vitro); or isoflurane (2%) plus OGD.

RESULTS

There were four immediate early genes/transcription factors (early growth response 1, c-fos, nerve growth factor-induced factor A and Knox-24) whose mRNA expression was increased to more than 1.4-fold of control levels under the conditions of isoflurane, OGD or isoflurane plus OGD. Isoflurane increased the mRNA expression of heme oxygenase, a 32-kDa heat-shock protein, and decreased the mRNA expression of caspase-2, calpain 1 and the Bcl-2-associated death agonist. These isoflurane effects were still apparent under the condition of isoflurane plus OGD. The mRNA expression of Gbeta1, early growth response 1 and the death effector domain-containing protein DEFT in the samples used for microarray assay was determined by reverse transcriptase-polymerase chain reaction, and the results were consistent with the patterns of changes across the experimental conditions as revealed by microarray technology.

CONCLUSION

Our data suggest that the effects of isoflurane on the mRNA expression of multiple genes in glial-neuronal cocultures are consistent with its neuroprotection against ischemia. A coordinated change in expression of many genes (increased expression of potentially protective gene and decreased expression of potentially damaging genes) after the exposure of isoflurane was revealed by this study.