Validação de genes diferencialmente transcritos no córtex pré-frontal em modelo animal de consumo de etanol

Abstract

The ethanol use disorder, the most consumed psychoactive substance in the world, is characterized by behavioral and physical symptoms that might include abstinence, tolerance and craving, besides being a worldwide public health problem. This disorder is a multifactorial illness with 50% heritability with no qualitative difference between men and women. The aim of this study was to identify different patterns of transcriptional regulation related to the addict phenotype in ethanol consumption in an animal model of free-choice. 80 Swiss male adult mice were used in which a group of 60 animals had access to ethanol and 20 control animals had access to water only. The experimental design was set with a week of ambiance; ten weeks of free choice treatment between ethanol and water solutions; two weeks of abstinence; two weeks of ethylic solutions restatement; and last two weeks adding quinine to the ethanol solutions. The animals were phenotypically classified as Light (L), those who had a preference for water and low consumption of ethanol; Heavy (H), those that had a preference for ethanol with a significant reduction in the consumption during the quinine addition phase; Addict (A), those who had constant preference for alcohol use throughout treatment; and Control (C), those who had access only to water. Relative quantification of the genes was performed by real time q-PCR with N = 20 animals (C=7; L=4; H=3; A=6) followed by statistical analysis of transcript levels. Next, the Pearson correlation analysis between the genes with a significant difference between groups was performed. Among those chosen for validation, the Camk2n1 and Pkp2 genes showed a downregulated profile in the Control group compared to the Addict group; the Drd2 gene showed a upregulated profile in the Addict group compared to the Light group; the Prox1 gene showed a upregulated profile in the Heavy group compared to the Control group; and the Mobp gene showed a tendency to downregulation in the Control group compared to the other groups. These different transcription patterns have been associated to the presence of alcohol, in the Camk2n1 and Mobp genes; to the loss of control in the ethanol consumption, in the Pkp2 and Drd2 genes; and to the amount of consumed ethylic solution, in the Prox1 gene. The majority of these genes encode membrane proteins that bind to ions and other proteins participating in regulations, responses to stimuli and metabolic processes. In addition, Pearson correlation analysis showed that the Camk2n1-Pkp2 and Drd2-Pkp2 genes have a strong positive correlation. Thus, we conclude that chronic ethanol intake is related to transcriptional changes in the prefrontal cortex in this animal model and for the first time, we demonstrated the possible involvement of Pkp2 gene in loss of control over the ethanol consumption.