Perfil de expressão gênica em células trofoblásticasbovinas durante a infecção por Brucella abortus

Abstract

Bovine brucellosis, caused by the Brucella abortus, is very important as a cause of abortion particularly atthe end of gestation. The study of the interaction between B. abortus and trophobastic cells is essential fora better understanding the pathogenesis of the Brucella-induced placentitis. The goal of this study was toevaluate the profile of gene expression in the bovine placenta during the infection with B abortus by usingexplants of chorioallantoic membrane as an alternative method for the ex vivo study of the pathogenesisof bovine brucelosis. The explants were inoculated with B. abortus strain 2308 (1.0 x 107 CFU) for fourhours to assess the trophoblastic gene expression profile during infection. Cytokines and chemokinesexpression in trophoblastic cells was assessed at six and 12 hours post infection. In addition, placentomesfrom experimentally infected cows were used in this study. Microarray and real time RT-PCR were usedfor evaluation of gene expression in trophoblastic cell. The microarray data demonstrated a suppression inthe profile of pro- inflammatory gene expression in chorioallantoic membrane explants at four hours postinfection. Infection of the explants with B. abortus resulted in a significant upregulation of proinflammatorygenes, namely GCP-2 and IL-8, at 12, but not at 6 hours after inoculation. Placentomes ofexperimentally infected cows had an upregulation of these chemokines (GCP-2 and IL-8). Theassociation of the explant model with methods for assessment of gene expression proved to be useful forstudying host-pathogen interactions. A pro-inflammatory gene expression response was not observed inthe early stages of infection of bovine trophoblastic cells with B. abortus. However, these data indicated atrophoblastic pro-inflammatory gene expression response at later time-points, which may play a role ineliciting neutrophil influx. This trophoblastic response is likely to contribute to the pathogenesis ofplacentitis, and consequently abortion.