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Toomey LM, Bartlett CA, Gavriel N, McGonigle T, Majimbi M, Gopalasingam G, Rodger J, Fitzgerald M. Comparing modes of delivery of a combination of ion channel inhibitors for limiting secondary degeneration following partial optic nerve transection. Sci Rep 2019; 9:15297. [PMID: 31653948 PMCID: PMC6814709 DOI: 10.1038/s41598-019-51886-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 10/07/2019] [Indexed: 11/28/2022] Open
Abstract
Injury to the central nervous system is exacerbated by secondary degeneration. Previous research has shown that a combination of orally and locally administered ion channel inhibitors following partial optic nerve injury protects the myelin sheath and preserves function in the ventral optic nerve, vulnerable to secondary degeneration. However, local administration is often not clinically appropriate. This study aimed to compare the efficacy of systemic and local delivery of the ion channel inhibitor combination of lomerizine, brilliant blue G (BBG) and YM872, which inhibits voltage-gated calcium channels, P2X7 receptors and Ca2+ permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors respectively. Following a partial optic nerve transection, adult female PVG rats were treated with BBG and YM872 delivered via osmotic mini pump directly to the injury site, or via intraperitoneal injection, both alongside oral administration of lomerizine. Myelin structure was preserved with both delivery modes of the ion channel inhibitor combination. However, there was no effect of treatment on inflammation, either peripherally or at the injury site, or on the density of oligodendroglial cells. Taken together, the data indicate that even at lower concentrations, the combinatorial treatment may be preserving myelin structure, and that systemic and local delivery are comparable at improving outcomes following neurotrauma.
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Affiliation(s)
- Lillian M Toomey
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Perth, 6009, Western Australia, Australia
- Curtin Health Innovation Research Institute, Curtin University, Sarich Neuroscience Research Institute Building, 8 Verdun St, Nedlands, 6009, Western Australia, Australia
- Perron Institute for Neurological and Translational Science, Sarich Neuroscience Research Institute Building, 8 Verdun St, Nedlands, 6009, Western Australia, Australia
| | - Carole A Bartlett
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Perth, 6009, Western Australia, Australia
| | - Nikolas Gavriel
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Perth, 6009, Western Australia, Australia
| | - Terence McGonigle
- Curtin Health Innovation Research Institute, Curtin University, Sarich Neuroscience Research Institute Building, 8 Verdun St, Nedlands, 6009, Western Australia, Australia
| | - Maimuna Majimbi
- Curtin Health Innovation Research Institute, Curtin University, Sarich Neuroscience Research Institute Building, 8 Verdun St, Nedlands, 6009, Western Australia, Australia
| | - Gopana Gopalasingam
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Perth, 6009, Western Australia, Australia
| | - Jennifer Rodger
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Perth, 6009, Western Australia, Australia
- Perron Institute for Neurological and Translational Science, Sarich Neuroscience Research Institute Building, 8 Verdun St, Nedlands, 6009, Western Australia, Australia
| | - Melinda Fitzgerald
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Perth, 6009, Western Australia, Australia.
- Curtin Health Innovation Research Institute, Curtin University, Sarich Neuroscience Research Institute Building, 8 Verdun St, Nedlands, 6009, Western Australia, Australia.
- Perron Institute for Neurological and Translational Science, Sarich Neuroscience Research Institute Building, 8 Verdun St, Nedlands, 6009, Western Australia, Australia.
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Bartlett CA, Fitzgerald M. Partial Transection of Adult Rat Optic Nerve as a Model of Secondary Degeneration in the Central Nervous System. Bio Protoc 2018; 8:e3118. [PMID: 34532560 DOI: 10.21769/bioprotoc.3118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 03/20/2018] [Indexed: 11/02/2022] Open
Abstract
Injury to the central nervous system is characterized by damage that spreads from the initial point of impact into the surrounding adjacent tissue, in a phenomenon referred to as secondary degeneration. The optic nerve can be used to effectively model injury and secondary degeneration to white matter tracts. Partial transection of the dorsal aspect of the nerve leaves the ventral aspect initially undamaged but vulnerable to secondary degeneration, allowing study of tissue exclusively vulnerable to secondary degeneration. Thus the partial optic nerve transection model of secondary degeneration is a valuable tool to study the pathology of spreading damage following neurotrauma and can be used to assess potential efficacy of therapeutic strategies.
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Affiliation(s)
- Carole A Bartlett
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Nedlands 6009 Western Australia, Australia.,Curtin Health Innovation Research Institute, Curtin University, Belmont, Australia
| | - Melinda Fitzgerald
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Nedlands 6009 Western Australia, Australia.,Curtin Health Innovation Research Institute, Curtin University, Belmont, Australia.,Perron Institute for Neurological and Translational Science, Nedlands 6009 Western Australia, Australia
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Cytokine and Growth Factor Activation In Vivo and In Vitro after Spinal Cord Injury. Mediators Inflamm 2016; 2016:9476020. [PMID: 27418745 PMCID: PMC4935915 DOI: 10.1155/2016/9476020] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 05/18/2016] [Indexed: 12/22/2022] Open
Abstract
Spinal cord injury results in a life-disrupting series of deleterious interconnected mechanisms encompassed by the primary and secondary injury. These events are mediated by the upregulation of genes with roles in inflammation, transcription, and signaling proteins. In particular, cytokines and growth factors are signaling proteins that have important roles in the pathophysiology of SCI. The balance between the proinflammatory and anti-inflammatory effects of these molecules plays a critical role in the progression and outcome of the lesion. The excessive inflammatory Th1 and Th17 phenotypes observed after SCI tilt the scale towards a proinflammatory environment, which exacerbates the deleterious mechanisms present after the injury. These mechanisms include the disruption of the spinal cord blood barrier, edema and ion imbalance, in particular intracellular calcium and sodium concentrations, glutamate excitotoxicity, free radicals, and the inflammatory response contributing to the neurodegenerative process which is characterized by demyelination and apoptosis of neuronal tissue.
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