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Characterising a new sheep model of Parkinson's disease using unilateral intracerebral injection of 6-hydroxydopamine into the substantia nigra
  • +4
  • Ashik Banstola,
  • Nicolas Vautrelle,
  • David Bergin,
  • Mohammad Younus,
  • Kushan Gandhi,
  • Shakila Rizwan,
  • John Reynolds
Ashik Banstola
University of Otago
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Nicolas Vautrelle
University of Otago
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David Bergin
University of Otago
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Mohammad Younus
University of Otago
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Kushan Gandhi
University of Otago
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Shakila Rizwan
University of Otago
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John Reynolds
University of Otago

Corresponding Author:john.reynolds@otago.ac.nz

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Abstract

New therapeutic agents developed for treating neurological disorders are often tested successfully on rodents, and yet 80–90% of these prove ineffective when transitioning to clinical application. Testing in an appropriate large-animal model should improve translational success and is frequently expected by regulatory bodies. In this project, we aimed to establish a novel sheep model of Parkinson’s disease as a large-brained experimental model for translational research. Our objective was to create a sheep model of Parkinson’s disease by unilaterally infusing the neurotoxin 6-hydroxydopamine into the substantia nigra pars compacta. This approach, previously used to induce parkinsonism in rat and non-human primate models, causes dopaminergic imbalance and induces rotational behaviour in quadrupeds challenged with dopaminergic receptor agonists. In the present sheep study, the mixed dopamine receptor agonist apomorphine, 0.25 mg/kg, and dopamine D2 agonist ropinirole, 0.16 mg/kg, were used to induce rotational behaviour and confirm dopamine depletion. Behavioural signs were then measured and characterised in the field using automated movement tracking with simultaneous video recordings. Post-mortem, the extent of the 6-hydroxydopamine lesions were evaluated through tyrosine hydroxylase immunohistochemistry and quantifying levels of catecholamines (dopamine, 3,4-dihydroxyphenylacetic acid, and homovanilic acid) quantified using high-performance liquid chromatography. Our new sheep model of Parkinson’s disease using 6-hydroxydopamine is safe and offers a number of regulatory, ethical, and financial advantages over non-human primate 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine models. It provides a platform to evaluate novel anti-parkinsonian agents and medical devices with the promise of greater success for translation into clinical application than has been achieved using small animal models.
31 Jul 2024Submitted to European Journal of Neuroscience
02 Aug 2024Submission Checks Completed
02 Aug 2024Assigned to Editor
03 Aug 2024Review(s) Completed, Editorial Evaluation Pending
04 Aug 2024Reviewer(s) Assigned
02 Sep 2024Editorial Decision: Revise Major