Decreased Bdnf expression and reduced social behavior in periadolescent rats following prenatal stress.

Prenatal stress (PNS) is a risk factor for the development of neuropsychiatric disorders. This study was aimed at assessing, in a rodent model, changes in gene expression profiles and behavioral output as a result of PNS, during periadolescence, a critical developmental period for the onset of psychopathology. Social behavior was studied in a standardized social interaction paradigm and the expression of Brain-Derived Neurotrophic Factor (Bdnf), a marker of neuronal plasticity, and of inhibitory and excitatory mechanisms (Na(+)-K(+)-2Cl(-) and K(+)-Cl(-) cotransporters ratio, NKCC1/KCC2) was analyzed. Results indicate that PNS reduced Bdnf transcripts while increasing the NKCC1/KCC2 ratio, primarily in the hippocampus. In the prefrontal cortex, changes in Bdnf were found to be gender-dependent. These effects were accompanied by reduced levels of affiliative and investigative social behaviors. Interestingly, interaction with non-stressed subjects was able to improve sociality in PNS rats suggesting that the social environment could be exploited for therapeutic intervention.