Analysis of differential gene expression in Mus spretus mice exposed to p,p’-DDE

The complexity of environmental systems requires the use of holistic methodologies to conduct studies of contamination effects over individuals who inhabit specific polluted areas. Microarrays are an appropriate tool since they allow the simultaneous expression analysis of thousand genes. As an omic and unbiased technology, it allows for the identification of novel biological responses within certain environmental conditions. A commercial microarray based on probes of the Mus musculus entire genome has been used in order to study transcriptional changes in M. spretus mice exposed to p,p’-DDE, a metabolic by-product of the organochlorine pesticide DDT, whose use is nowadays limited due to the hazardous environmental impact it causes. The success of this approach lies in the high phylogenetic closeness between M. spretus, a species of large environmental interest, whose genome is not sequenced, and the laboratory mouse M. musculus. The results obtained with these heterologous microarrays, verified by qRT-PCR, indicate that the exposed mice to this compound present alterations in their gene expression profiles relative to control animals. Based on the data obtained herein, it can be inferred that mice exposed to p,p’-DDE show alterations in lipids and carbohydrates metabolism, in the immune response, cell cycle control and signaling and molecular transport processes. Four seven-week Mus spretus (inbred SPRET/EiJ strain) were fed for 30 days with Harlan diet supplemented with p,p'-DDE (450 mg/kg) dissolved in corn oil. Control group (four mice) was fed only with Harlan diet and corn oil.