Widespread early dendritic injury associated with loss of cortical MAP-2 immunostaining in a focal ovine head impact model.

Dendritic pathology associated with traumatic brain injury may be identified by microtubule associated protein-2 (MAP-2) immunohistochemistry. The aim of this study was to examine the dendritic response in the cerebral cortical mantle in an ovine head impact model using MAP-2 immunostaining as a marker for dendritic injury. The loss of cortical MAP-2 immunoreactivity at 2 h was recorded and quantitated using a computerised image analysis system applied to standard coronal brain sections obtained from 10 impacted and 3 control sheep. Coup and contrecoup cortical contusions were present in 9 of 10 impacted brains examined 2 h after injury. MAP-2 immunoreactivity was lost in all areas of cortical contusion irrespective of site and in otherwise histologically normal cortex. MAP-2 immunostaining was lost in over 45% of the whole cortical area (range 32-54%) and only 2% (range 0-5.5%) was associated with contusions. This study has shown that there is widespread loss of MAP-2 immunostaining following head impact in the cerebral cortical mantle (up to 54%) suggestive of early dendritic injury.