Effect of impact on different regions of the head of lambs

The heads of anaesthetized lambs aged 4 5 weeks were subject to impact (tem poral, frontal or occipital) of constant strength with a humane stunner. Tw o hours later, the brains were perfusion-fixed with 4 degrees paraformaldeh yde and serial whole coronal slices processed by routine methods. Sections were stained with haematoxylin and eosin or labelled with a monoclonal anti body to amyloid precursor protein, a sensitive marker of axonal injury and neuronal reaction. Microscopical evaluation of axonal, neuronal and vascula r damage was performed with a quantitative grid system. Frontal impact prod uced the greatest damage, followed by occipital then temporal impact. An un usual lesion found in the majority of lambs subjected to impact was multifo cal necrosis of the cerebellar granular layer. The findings should assist c linicians in evaluating the probable outcome of traumatic head injury in do mestic animals. (C) 2001 Harcourt Publishers Ltd.