Sex differences in somatic and sensory motor development after neonatal anoxia in Wistar rats

Currently, one of the important causes of brain injury in new-borns is the neonatal anoxia which impacts the perinatology services worldwide. Animal models of anoxia have been used to assess its effects at cellular and behavioural levels in all ages, but few studies focus on sex differences. This study aimed to investigate some physical parameters of development, sensorimotor alterations, early neurological reflexes as well as the density of cells in motor and sensorimotor cerebral cortex of adolescent rats submitted to neonatal anoxia. The results presented significant differences in most of the evaluated parameters, such as body weight and lenght, medio-lateral head axis, eruption of superior incisor, palmar grasp, auditory startle, negative geotaxis, showing that neonatal anoxia affects physical parameters and neurological development, with sex differences. Cellular analysis revealed decreased amount of neurons in motor cortex and primary sensory hind limb and forelimb regions in anoxic group, along with gender difference, as compared to control groups. There is an important rationale for performing early assessment of sensorimotor deficits as there is similarity of the model with high risk human neonates and the sequelae in later life periods, which can be inferred from the present results with suggestion of a possible correlation between sensorimotor development delay and cellular changes in sensorimotor cortex. Furthermore, these observed sex dependent alterations certainly will address further studies and should be considered especially in treatments and strategies to avoid or minimize the neonatal anoxic effects.