Approximately 2.9-9.0 newborns of 1000 infants experience some degree of perinatal ischemic-anoxic or prolonged anoxic insult. The interruption of perfusion and oxygenation is the main cause of cerebral damage in neonates, and it has a big impact on the development of pathologies on adult age (such as epilepsy and schizophrenia). The evaluation of the behavioral damage related to hypoxia can be very interesting in the establishment of preventive cares that aim to hinder the deleterious effects that neonatal events could cause on adult life.
The objective of this work is to evaluate behavioral differences on mice that had suffered neonatal hypoxia compared to two control groups.
Thirty-six 7-days-old Swiss male mice were distributed in three different groups: hypoxia (H), maternal separation control (MS) and no handling control (NH). The H group had undergone 10% oxygen during 6 hours/day for 6 days and MS group was maintained in normoxia, but it was separated from their mothers during the same time as group H.
When mice completed 3 months old, they were tested on the plus-maze discriminative avoidance task (DAT), a model of learning/memory and on open-field (OF).
The DAT results has shown that animal groups had no significantly differences on memory (percentage of time spent in the aversive arm) or motor activity (total number of entries) on both sessions, while anxiety (percentage of time spent in the open arms) was significantly higher on training session for the groups H and MS when compared to NH group (p<0.05). On the other hand, H group presented higher hearing behavior when compared to NH and also presented increase in locomotion time comparing to both control groups on OF.
These data indicate that maternal separation could cause anxiety in mice on adult life and also that our hypoxia model did not produce any behavioral effect in the elevated plus-maze test, although on OF our model has shown different on hearing behavior and on locomotion time.
FINANCIAL SUPPORT: FAPESP, CNPq and AFIP.