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Methylprednisolone exacerbates axonal loss following optic nerve trauma in rats
Kenneth D. Steinsapir1, Robert A. Goldberg, Shini Sinha
1Orbital and Ophthalmic Plastic Surgery Division, Jules Stein Eye Institute, Los Angeles, USA.
Abstract:
Purpose: This study investigates the clinical dogma that very high doses of methylprodnisolone helpful in spinal cord injury are also helpful in optic nerve trauma. Methods: The right optic nerve of 29 male rats received a 5 second traumatic crush followed 30 minutes later by one of five intravenous treatments (methylprednisolone 30 mg/kg, 60 mg/kg, 90 mg/kg, 120 mg/kg, or saline). Treatment was continued for three additional administrations at 6 hour intervals. Untreated sham controls (n=7) were also prepared. Six weeks after injury, animals were sacrificed, perfused and optic nerves systematically counted. Results: Axon counts (means +/- s.e.m.) were as follows: Saline = 16,670+/-8,900 (n=5); Methylprednisolone: 30 mg/kg = 8,098+/-4,741 (n=5); 60 mg/kg=6,925+/-6,517 (n=4); 90 mg/kg=2,663+/-2,653 (n=4); 120 mg/kg=6,149+/-3,487 (n=6). Consequently, the data revealed that saline treated animals retained more axons than those that were administered methylprednisolone (p<0.02). Conclusions: We conclude that methylprednisolone exacerbates axonal loss following crush injury in the rat optic nerve. Based on the results of this study, clinical studies of traumatic optic neuropathy in the future should also examine the possibility that corticosteroid treatment may have an adverse effect on visual outcome following optic nerve trauma.
Insights
Methylprednisolone treatment worsened vision loss in rats with optic nerve crush injuries. This suggests corticosteroids may negatively impact outcomes for traumatic optic neuropathy patients.
Area of Science:
- Neuroscience
- Ophthalmology
- Pharmacology
Background:
- High-dose methylprednisolone is used for spinal cord injury.
- Its efficacy in traumatic optic nerve injury is debated.
- Corticosteroids are commonly considered for optic nerve trauma.
Purpose of the Study:
- To investigate if methylprednisolone benefits optic nerve trauma.
- To challenge the clinical dogma of its use in optic nerve injury.
Main Methods:
- Rats underwent optic nerve crush injury.
- Intravenous methylprednisolone (30-120 mg/kg) or saline was administered.
- Axon counts were performed six weeks post-injury.
Main Results:
- Saline treatment resulted in significantly more retained axons than methylprednisolone.
- Methylprednisolone was associated with increased axonal loss.
- The p-value was less than 0.02, indicating statistical significance.
Conclusions:
- Methylprednisolone exacerbates axonal loss in rat optic nerve crush injury.
- Future clinical trials should assess potential adverse effects of corticosteroids in traumatic optic neuropathy.