A controlled impact of optic nerve as a new model of traumatic optic neuropathy in Mouse

Ahmed S. Ibrahim, Khaled Elmasry, Ming Wan, Samer Abdulmoneim, Amber Still, Farid Khan, Abraham Khalil, Alan Saul, Md Nasrul Hoda, Mohamed Al-Shabrawey

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

PURPOSE. Traumatic optic neuropathy (TON) is the most feared visual consequence of head and ocular trauma in both military and civilian communities, for which standard treatment does not exist. Animal models are critical for the development of novel TON therapies as well as the understanding of TON pathophysiology. However, the models currently used for TON have some limitations regarding consistency and mirroring the exact pathological progression of TON in closed ocular trauma. In this study, we modified the model of controlled cortical impact and adapted it for studying TON. METHODS. We defined new standardized procedures to induce TON in mice, wherein the optic nerve is reproducibly exposed to a graded controlled impact of known velocity to produce a graded deficit in retinal ganglion cell (RGC) electrophysiological functions. RESULTS. The key results of validating this newly modified model, ‘‘controlled orbital impact (COI),’’ included (1) the injury parameters (velocity as well as contusion depth and time), which were quantifiable and manageable to generate a wide range of TON severities; (2) a reproducible endpoint of diminished positive scotopic threshold response (pSTR) has been achieved without the interference of surgical variability and destruction of surrounding tissues; (3) the contralateral eyes showed no significant difference to the eyes of naïve mice, allowing them to be used as an internal control to minimize interindividual variability among mice; and (4) the occurrence of injury-associated mortality and/or ocular comorbidity was rare. CONCLUSIONS. Taken together, this model overcomes some limitations of prior TON mouse models and provides an innovative platform to identify therapeutic targets for neuroprotection and/or neurorestoration following traumatic ocular injury.

Original languageEnglish (US)
Pages (from-to)5548-5557
Number of pages10
JournalInvestigative Ophthalmology and Visual Science
Volume59
Issue number13
DOIs
StatePublished - Nov 2018

Fingerprint

Optic Nerve Injuries
Optic Nerve
Wounds and Injuries
Eye Injuries
Retinal Ganglion Cells
Contusions
Craniocerebral Trauma
Comorbidity
Animal Models

Keywords

  • Controlled impact
  • Microglia
  • PSTR
  • Retinal ganglion cell (RGC)
  • Scotopic threshold response
  • TON
  • Traumatic optic neuropathy

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

Cite this

A controlled impact of optic nerve as a new model of traumatic optic neuropathy in Mouse. / Ibrahim, Ahmed S.; Elmasry, Khaled; Wan, Ming; Abdulmoneim, Samer; Still, Amber; Khan, Farid; Khalil, Abraham; Saul, Alan; Hoda, Md Nasrul; Al-Shabrawey, Mohamed.

In: Investigative Ophthalmology and Visual Science, Vol. 59, No. 13, 11.2018, p. 5548-5557.

Research output: Contribution to journalArticle

Ibrahim, AS, Elmasry, K, Wan, M, Abdulmoneim, S, Still, A, Khan, F, Khalil, A, Saul, A, Hoda, MN & Al-Shabrawey, M 2018, 'A controlled impact of optic nerve as a new model of traumatic optic neuropathy in Mouse', Investigative Ophthalmology and Visual Science, vol. 59, no. 13, pp. 5548-5557. https://doi.org/10.1167/iovs.18-24773
Ibrahim, Ahmed S. ; Elmasry, Khaled ; Wan, Ming ; Abdulmoneim, Samer ; Still, Amber ; Khan, Farid ; Khalil, Abraham ; Saul, Alan ; Hoda, Md Nasrul ; Al-Shabrawey, Mohamed. / A controlled impact of optic nerve as a new model of traumatic optic neuropathy in Mouse. In: Investigative Ophthalmology and Visual Science. 2018 ; Vol. 59, No. 13. pp. 5548-5557.
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AU - Elmasry, Khaled

AU - Wan, Ming

AU - Abdulmoneim, Samer

AU - Still, Amber

AU - Khan, Farid

AU - Khalil, Abraham

AU - Saul, Alan

AU - Hoda, Md Nasrul

AU - Al-Shabrawey, Mohamed

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N2 - PURPOSE. Traumatic optic neuropathy (TON) is the most feared visual consequence of head and ocular trauma in both military and civilian communities, for which standard treatment does not exist. Animal models are critical for the development of novel TON therapies as well as the understanding of TON pathophysiology. However, the models currently used for TON have some limitations regarding consistency and mirroring the exact pathological progression of TON in closed ocular trauma. In this study, we modified the model of controlled cortical impact and adapted it for studying TON. METHODS. We defined new standardized procedures to induce TON in mice, wherein the optic nerve is reproducibly exposed to a graded controlled impact of known velocity to produce a graded deficit in retinal ganglion cell (RGC) electrophysiological functions. RESULTS. The key results of validating this newly modified model, ‘‘controlled orbital impact (COI),’’ included (1) the injury parameters (velocity as well as contusion depth and time), which were quantifiable and manageable to generate a wide range of TON severities; (2) a reproducible endpoint of diminished positive scotopic threshold response (pSTR) has been achieved without the interference of surgical variability and destruction of surrounding tissues; (3) the contralateral eyes showed no significant difference to the eyes of naïve mice, allowing them to be used as an internal control to minimize interindividual variability among mice; and (4) the occurrence of injury-associated mortality and/or ocular comorbidity was rare. CONCLUSIONS. Taken together, this model overcomes some limitations of prior TON mouse models and provides an innovative platform to identify therapeutic targets for neuroprotection and/or neurorestoration following traumatic ocular injury.

AB - PURPOSE. Traumatic optic neuropathy (TON) is the most feared visual consequence of head and ocular trauma in both military and civilian communities, for which standard treatment does not exist. Animal models are critical for the development of novel TON therapies as well as the understanding of TON pathophysiology. However, the models currently used for TON have some limitations regarding consistency and mirroring the exact pathological progression of TON in closed ocular trauma. In this study, we modified the model of controlled cortical impact and adapted it for studying TON. METHODS. We defined new standardized procedures to induce TON in mice, wherein the optic nerve is reproducibly exposed to a graded controlled impact of known velocity to produce a graded deficit in retinal ganglion cell (RGC) electrophysiological functions. RESULTS. The key results of validating this newly modified model, ‘‘controlled orbital impact (COI),’’ included (1) the injury parameters (velocity as well as contusion depth and time), which were quantifiable and manageable to generate a wide range of TON severities; (2) a reproducible endpoint of diminished positive scotopic threshold response (pSTR) has been achieved without the interference of surgical variability and destruction of surrounding tissues; (3) the contralateral eyes showed no significant difference to the eyes of naïve mice, allowing them to be used as an internal control to minimize interindividual variability among mice; and (4) the occurrence of injury-associated mortality and/or ocular comorbidity was rare. CONCLUSIONS. Taken together, this model overcomes some limitations of prior TON mouse models and provides an innovative platform to identify therapeutic targets for neuroprotection and/or neurorestoration following traumatic ocular injury.

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KW - Scotopic threshold response

KW - TON

KW - Traumatic optic neuropathy

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