J Korean Med Sci.  2005 Feb;20(1):132-138. 10.3346/jkms.2005.20.1.132.

Effects of Methylprednisolone on the Neural Conduction of the Motor Evoked Potentials in Spinal Cord Injured Rats

• Lee BH
• Lee KH
• Yoon DH
• Kim UJ
• Hwang YS
• Park SK
• Choi JU
• Park YG

• KMID: 1781740
• DOI: http://doi.org/10.3346/jkms.2005.20.1.132

Abstract

Methylprednisolone (MP), a glucocorticoid steroid, has an anti-inflammatory action and seems to inhibit the formation of oxygen free radicals produced during lipid peroxidation in a spinal cord injury (SCI). However, the effects of MP on the functional recovery after a SCI is controversial. The present study was conducted to determine the effects of MP on the recovery of neural conduction following a SCI. A SCI was produced using the NYU spinal cord impactor. A behavioral test was conducted to measure neurological disorders, and motor evoked potentials (MEPs) were recorded. According to the behavioral test, using BBB locomotor scaling, MP-treated animals showed improved functional recoveries when compared to salinetreated animals. MEP latencies in the MP-treated group were shortened when compared to those in the control group. Peak amplitudes of MEPs were larger in the MP-treated group than those in the control group. The thresholds of MEPs tended to be lower in the MP-treated group than those in the control group. These results suggest that MP may improve functional recovery after a SCI.

Keyword

Spinal Cord Injuries; Methylprednisolone; Behavior; Evoked Potentials; Recovery of Function

MeSH Terms

Animals
Disease Models, Animal
Electrophysiology
Evoked Potentials, Motor/*drug effects
Free Radicals
Glucocorticoids/metabolism
Male
Methylprednisolone/*pharmacology
Neurons/*drug effects
Oxygen/metabolism
Rats
Rats, Sprague-Dawley
Receptors, Glucocorticoid/metabolism
Research Support, Non-U.S. Gov't
Sodium Chloride/pharmacology
Spinal Cord/pathology
Spinal Cord Injuries/*drug therapy
Time Factors

Figure

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  Fig. 1 Changes in locomotor deficits after a spinal cord injury. Behavioral scores were measured by the BBB methods. The BBB scores decrease after an injury and slowly and gradually increase. Intraperitoneally injected MP promoted a behavioral recovery following a SCI when compared to the saline-treated control animals. Data were expressed as mean±s.e.m. Asterisks (*) indicate a significant difference between the MP- and saline-treated groups at each post-operative time point (p<0.05).

• 

  Fig. 2 Representative motor evoked potentials (MEPs) recorded in saline-treated SCI (upper left), MP-treated SCI (lower left), and intact (right) animals. Note the different amplitude scales.

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  Fig. 3 Changes in latencies of MEPs after MP administration in the SCI animals. (A) Comparison of the initial latencies (the rising phase of MEPs) in the MP- and saline-treated groups at 2, 4, and 6 weeks p.o. (B) Comparison of the N1 (the first negative deflection) latencies in the MP- and saline-treated groups at 2, 4, and 6 weeks p.o. (C) Comparison of the P1 (the first positive deflection) latencies in the MP- and saline-treated groups at 2, 4, and 6 weeks p.o. Data were expressed as mean±s.e.m. Asterisks (*) indicate a significant difference between the MP- and saline-treated groups at each post-operative time point (p<0.05).

• 

  Fig. 4 Changes in amplitudes of MEPs after the MP administration in the SCI animals. (A) Comparison of the N1 (the first negative deflection) amplitudes in the MP- and saline-treated groups at 2, 4, and 6 weeks p.o. (B) Comparison of the P1 (the first positive deflection) amplitudes in the MP- and saline-treated groups at 2, 4, and 6 weeks p.o. Data were expressed as mean±s.e.m. Asterisks (*) indicate a significant difference between the MP- and saline-treated groups at each post-operative time point (p<0.05).

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