J Korean Orthop Assoc.  2009 Aug;44(4):414-421.

The Neuroprotective Effect of Combination Therapy of Polyethylene Glycol and Magnesium Sulfate in Acute Spinal Cord Injury

• Lee JY
• You JW
• Sohn HM
• Lee SJ
• Kwon BK

Abstract

PURPOSE
To evaluate the neuroprotective effect of combination therapy of polyethylene glycol (PEG) and magnesium sulfate (MgSO4) after a spinal cord injury. MATERIALS AND METHODS: Twenty Sprague Dawley male rats (300-350 gm) had a spinal cord injury after T9/10 laminectomy using an Ohio State University (OSU) impactor under intraperitoneal anesthesia. The animals were randomized to receive either PEG (1 g/kg)+MgSO4 (300 mg/kg) or saline (2 ml) via carotid vein after 2 hours of injury and then every 6 hours for 5 times. The behavioral outcome assessments were performed on days 2, 4 and 7, and then every week using the Basso, Bresnahan, and Beattie (BBB) score and subscore. The animals also underwent sensory threshold testing using a von Frey monofilament device and gait analysis with Catwalk program before and 6 weeks after cord injury. The animals were sacrificed at the end of 6 weeks and histologic assessment was performed to measure the areas of white and gray matter. RESULTS: For the animals treated with PEG+MgSO4 and saline, the mean BBB scores at 6 weeks post-injury were 13.3+/-0.3, 11.4+/-0.2 and the BBB subscores were 9.1+/-1.1, 4.4+/-1.2 respectively (p<0.05). No significant differences were found in sensory testing and gait analysis between the two groups. Histologic assessment revealed no significant difference in gray matter sparing but the areas of white matter at the lesion epicenter were 0.68+/-0.2, 0.41+/-0.04 mm2 in the PEG+MgSO4 and saline groups respectively, which indicated significant sparing of white matter in PEG+MgSO4 group (p<0.05). CONCLUSION: The combination therapy of polyethylene glycol and magnesium sulfate improved the motor function and showed significant histological sparing of the spinal cord after an acute spinal cord injury in rats.

Keyword

Acute spinal cord injury; Polyethylen glycol; Magnesium sulfate

MeSH Terms

Anesthesia
Animals
Gait
Humans
Laminectomy
Magnesium
Magnesium Sulfate
Male
Neuroprotective Agents
Ohio
Polyethylene
Polyethylene Glycols
Rats
Sensory Thresholds
Spinal Cord
Spinal Cord Injuries
Veins
Magnesium
Magnesium Sulfate
Neuroprotective Agents
Polyethylene
Polyethylene Glycols

Figure

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  Fig. 1 Administration of PEG+MgSO4 using port system. Injected pharmacologic agent is administrated to blood via external carotid vein.

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  Fig. 2 Foot prints (A-C) and gait diagram (D) using Catwalk program. (A) Forepaws only, (B) Hindpaws only, (C) All four paws combined. Regularity index, base of support, swing duration and stride length were measured.

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  Fig. 3 (A) BBB score. The PEG+MgSO4-treated animals showed improved open-field locomotor (BBB) scores compared with the control animals (*, p<0.05). (B) BBB subscore. The PEG+MgSO4-treated animals showed improved BBB subscores compared with the control animals (*, p<0.05).

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  Fig. 4 Pinprick sensory test. There was no significant difference between the two groups after 6 weeks post-injury (p>0.05).

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  Fig. 5 Histology assessment. There was no significant difference of grey matter sparing between the two groups. The PEG+MgSO4-treated animals showed increased sparing of the white matter at the injury epicenter and at 0.2 mm rostral and 0.2 mm caudal (*, p<0.05).

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