Behavioural effects of near-term acute fetal hypoxia in a small precocial animal, the spiny mouse (Acomys cahirinus)

We have previously developed a model of near-term intra-uterine hypoxia producing significant neonatal mortality (37 ) in a small laboratory animal - the spiny mouse - which has precocial offspring at birth. The aim of the present study was to determine if this insult resulted in the appearance of behavioural abnormalities in those offspring which survived the hypoxic delivery. Behavioural tests assessed gait (using footprint patterns), motor coordination and balance on an accelerating rotarod, and spontaneous locomotion and exploration in an open field. We found that the near-term acute hypoxic episode produced a mild neurological deficit in the early postnatal period. In comparison to vaginally delivered controls, hypoxia pups were able to remain on the accelerating rotarod for significantly shorter durations on postnatal days 1-2, and in the open field they travelled significantly shorter distances, jumped less, and spent a greater percentage of time stationary on postnatal days 5 and 15. No changes were observed in gait. Unlike some rodent models of cerebral hypoxia-ischaemia, macroscopic examination of the brain on postnatal day 5 showed no gross cystic lesions, oedema or infarct. Future studies should be directed at identifying hypoxia-induced alterations in the function of specific brain regions, and assessing if maternal administration of neuroprotective agents can prevent against hypoxia-induced neurological deficits and brain damage that occur at birth.