OBJECTIVETo study the mechanism of electrophysiologic changes caused by different type of sodium salicylate injection.

METHODSDecapitated three group rats ( acute injected, chronic injected and normal rats ) separately, dissected the temporal bones to collect cochlea, and the otic capsules were removed. Then the cochlear materials from each groups were pooled and homogenized respectively, extracted the total RNA, obtained cDNA from purified total RNA by reversed transcription, cDNA were transcripted to cRNA probes in vitro. Hybridized the cRNA probes with tester chip to evaluate the quality of probes, if good, hybridized the probes with real chip. Obtained three gene expression profiles of different groups of cochlea Analyzed the differentially expressed genes among three groups by SOM. Analogized the SOM result to electrophysiologic changes. Then analyzed the genes in clusters of analog results by Gene Ontology. Then the genes in clusters of analog results were analyzed by Gene Ontology. Hsp27 was chosen to validate the result of gene chip using real time quantitative reverse transcription PCR ( RTQ RT-PCR).

RESULTSThe probes was good, and the chip hybridization results was credible. We obtained 6 clusters genes by SOM analysis, in which we choose cluster 3 and cluster 4 as candidate cluster. There were 46 genes in cluster 3 and 30 genes in cluster 4 employing GO analysis, which involved in cell communication, cell motility, metabolism, immune response and nerve ensheathment, et al. The result of RTQ RT-PCR showed high concordance with that of gene chip.

CONCLUSIONIt's a new method to study the mechanism of electrophysiologic changes caused by sodium salicylate by gene chip and SOM analysis.