| To discover the molecular mechanism by which organophosphate (OP) poisoning may produce and search for the functional protein related to OP-induced brain damage, the genes related to OP-induced brain damage were separated using suppression subtractive hybridization(SSH).Rats exposure to dichlorovos (12.5mg/kg, s.c.) produced tonic-clonic convulsions. Hippocampus of intoxicated and control rats were isolated immediately 20min after convulsions. mRNA of those were extracted and reverse-transcribed into cDNA. After ligating with two individual adaptors, the tester cDNA was denatured and hybridized with driver cDNA. The differentially expressed cDNAs in the tester were then picked out and cloned into pGEM-T cloning vector after PCR amplification. Slot blot was used for the expression pattern analysis of the obtained cDNA fragments. Positive clones were sequenced and analysed using GenBank database.In the present study, two-directional (forward and reverse) SSH was performed. We obtained 86 individual cDNA clones, 16 of them were examined by RNA slot hybridization. Eight sequences were identified of which three were over-expressed in the hippocampus of intoxicated rats, the others were downregulated. Clone No.03 is 98% homologous to part of gene sequences of 11-zinc finger protein. Clone No.09 is 99% homologous to beta-actin gene and No. 11 is high homologous to part of the regulator of G-protein signaling 5. It was found that the three known genes were associated with synaptic morphology, genes activation or repression, chromatin insulation and release of neurotransmitter. These results indicated that organophosphate poisoning had effects on the brain gene expression in rats. The results have provided a foundation for better understanding of the molecular basis of OP-induced brain damage and an approach to find possible medication for the disorder.
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