Neurological Examination of Sheep (Ovis aries) with Unilateral and Bilateral Quinolinic Acid Lesions of the Striatum Assessed by Magnetic Resonance Imaging

Acute toxic models of Huntington’s disease (HD) and Parkinson’s disease (PD) have been used extensively to study neuropathology and behavior in rodents and non-human primates, but not large animals. We have created an acute quinolinic acid (QA) model of HD in sheep (Ovis aries), first to investigate the clinical signs of ovine striatum pathology and second to assess the value of a veterinary neurological examination in the symptomology investigation. Sixteen sheep underwent two surgeries, four weeks apart, in which either QA or saline was infused into the left (unilateral) and then the right (bilateral) caudate nucleus. Neurological examinations were performed pre-surgically, two weeks after the unilateral surgery and eight weeks after the bilateral surgery. Examining veterinarians were blind to treatment group. Evidence of laterality and hind limb motor dysfunction was identified in the QA-lesioned sheep. The neurological examination identified clinical signs in two out of eight saline control sheep and four out of eight QA-lesioned sheep after the unilateral surgery and three out of eight saline control sheep and seven out of eight QA-lesioned sheep after the bilateral lesion surgery. There was no association between clinical profile and treatment group, or lesion size and location. While the neurological examination was moderately useful for identification of QA-lesioned sheep, it was not informative about lesion characteristics.