Methylprednisolone and membrane properties of primary cultures of mouse spinal cord

Neuroprotective role of hydralazine in rat spinal cord injury-attenuation of acrolein-mediated damage

Acrolein, an α,β-unsaturated aldehyde and a reactive product of lipid peroxidation, has been suggested as a key factor in neural post-traumatic secondary injury in spinal cord injury (SCI), mainly based on in vitro and ex vivo evidence. Here, we demonstrate an increase of acrolein up to 300%; the elevation lasted at least 2 weeks in a rat SCI model. More importantly, hydralazine, a known acrolein scavenger can provide neuroprotection when applied systemically. Besides effectively reducing acrolein, hydralazine treatment also resulted in significant amelioration of tissue damage, motor deficits, and neuropathic pain. This effect was further supported by demonstrating the ability of hydralazine to reach spinal cord tissue at a therapeutic level following intraperitoneal application. This suggests that hydralazine is an effective neuroprotective agent not only in vitro, but in a live animal model of SCI as well. Finally, the role of acrolein in SCI was further validated by the fact that acrolein injection into the spinal cord caused significant SCI-like tissue damage and motor deficits. Taken together, available evidence strongly suggests a critical causal role of acrolein in the pathogenesis of spinal cord trauma. Since acrolein has been linked to a variety of illness and conditions, we believe that acrolein-scavenging measures have the potential to be expanded significantly ensuring a broad impact on human health.

The dose-dependent neuroprotective effect of alpha-lipoic acid in experimental spinal cord injury

BACKGROUND AND PURPOSE

Free radical production after spinal cord injury (SCI) plays an important role in secondary damage. The aim of this study was to investigate neuroprotective effects of the powerful antioxidant alpha-lipoic acid (ALA) in a spinal cord clip compression injury model.

MATERIAL AND METHODS

Fifty-six Sprague-Dawley rats, weighing between 210 and 300 g, were randomly divided into seven groups. Spinal cord injury was performed by an aneurysm clip placed extradurally at the level of T9. Group 1 (sham) received laminectomy only. Group 2 (control) received SCI; Group 3 received 30 mg/kg of methylprednisolone sodium succinate (MPSS); Groups 4, 5, 6 and 7 received ALA at doses of 50, 100, 150, 200 mg/kg, respectively, via the intraperitoneal route immediately after SCI. The rats were neurologically tested 24 hours after trauma. Spinal cord samples from injury sites were harvested for measurement of lipid peroxidation products and histopathological evaluation.

RESULTS

Spinal cord malonyldialdehyde levels of rats in treatment groups decreased after administration of ALA. The difference between the trauma group and groups receiving MPSS-ALA was statistically significant. The difference between the ALA (50, 100, 150 mg/kg) and MPSS groups was insignificant. Group 7 (ALA 200 mg/kg) was excluded from the study because of the possible toxic effect. Alpha lipoic acid and MPSS had similar effects on spinal cord injury in terms of lipid peroxidation, neurological recovery and histopathological changes.

CONCLUSIONS

Alpha lipoic acid at a dose range of 50-150 mg/ kg is as effective as MPSS (30 mg/kg) in neuroprotection after SCI. Further, more detailed experimental studies are needed to determine the effects of ALA on the detrimental results of secondary SCI before its use in humans.

Effect of erythropoietin on brain tissue after experimental head trauma in rats

BACKGROUND

The purpose of this study was to investigate the effect of EPO on LPO, on ultrastructural findings, and on antiapoptotic bcl-2 and survivin gene expressions after TBI. The authors also compared the activity of EPO with that of MPSS.

METHODS

Wistar rats were divided into 6 groups: sham-operated, control, moderate TBI-alone (300 g/cm), TBI + EPO-treated (1000 IU/kg), TBI + MPSS-treated (30 mg/kg), and TBI + vehicle-treated (0.4 mL albumin solution) groups.

RESULTS

Compared with the levels in control and sham-operated animals, LPO was significantly elevated in rats in the trauma-alone group. The administration of EPO and MPSS significantly decreased the LPO levels (P < .05). Trauma also increases the antiapoptotic bcl-2 gene expression significantly at 24 hours postinjury (P < .05), but it has no effect on survivin expression. The EPO and MPSS treatments caused significant elevation in both gene expressions (P < .05). It is also showed that MPSS has more protective effect than EPO on brain ultrastructure, especially on the structure of small- (P < .05) and medium-sized myelinated axons, after TBI.

CONCLUSIONS

EPO has protective effects after moderate TBI, and this effect seems better than MPSS on antiapoptotic gene expression and LPO. The protection of cerebral subcellular organelles after traumatic injury is more prominent in MPSS-treated animals than EPO-treated animals quantitatively. This experimental study indicates that the benefits of EPO in the management of TBI have promising results and prompts further studies on the difference between EPO and MPSS in histopathological findings at the subcellular level.

Neuroprotective effect of etomidate on functional recovery in experimental spinal cord injury

OBJECTIVE

Primary impact to the spinal cord causes rapid oxidative stress after injury. To protect neural tissue, it is important to prevent secondary pathophysiological mechanisms. Etomidate, a strong antiexcitotoxic agent, stimulates the gamma aminobutyric acid (GABA) receptors. The purpose of this study was to investigate neurobehavioral and histological recovery and to evaluate the biochemical responses to treatment of experimental spinal cord injury (SCI) in rats with etomidate or methylprednisolone (MP) or both etomidate and MP.

MATERIAL AND METHODS

Seventy-two rats were randomly allocated into six groups: a control group (laminectomy alone), a trauma group (laminectomy+trauma), a methylprednisolone group (30 mg/kg MP), an etomidate group (2 mg/kg), a methylprednisolone and etomidate combined treatment group (30 mg/kg MP and 2 mg/kg etomidate) and a vehicle group. Six rats from each group were killed at the 24th hour after the injury. Malondialdehyde, glutathione, nitric oxide and xanthine oxidase levels were measured. Neurological functions of the remaining rats were recorded weekly. Six weeks after injury, all of those rats were killed for histopathological assessment.

RESULTS

Etomidate treatment revealed similar neurobehavioral and histopathological recovery to MP treatment 6 weeks after injury. Combined treatment did not provide additional neuroprotection.

CONCLUSION

Etomidate treatment immediately after spinal cord injury has similar neuroprotection to MP. In spite of different neuroprotection mechanisms, combined treatment with MP and etomidate does not provide extra protection.

The antioxidant effect of beta-Glucan on oxidative stress status in experimental spinal cord injury in rats

This study was performed to investigate the antioxidant effect of beta-Glucan in experimental spinal cord injury (SCI). Injury was produced using weight-drop technique in rats. beta-Glucan was given by intraperitoneal injection following trauma. The rats were sacrificed at the sixth day of injury. Oxidative stress status was assessed by measuring the spinal cord tissue content of Malonyldialdehyde (MDA), Superoxide Dismutase (SOD) and Gluthatione Peroxidase (GSH-Px) activities. No effect of beta-Glucan on SOD and MDA activities was found but, GSH-Px levels were found to decrease to the baseline (preinjury) levels when it was compared to untreated group (U=0.000; p=0.002). According to our results, beta-Glucan works like a scavenger and has an antioxidant effect on lipid peroxidation in spinal cord injury.

The Mitochondrial Uncoupling Agent 2,4-Dinitrophenol Improves Mitochondrial Function, Attenuates Oxidative Damage, and Increases White Matter Sparing in the Contused Spinal Cord

The purpose of this study was to investigate the potential neuroprotective efficacy of the mitochondrial uncoupler 2,4-dinitrophenol (DNP) in rats following a mild to moderate spinal cord contusion injury. Animals received intraperitoneal injections of vehicle (DMSO) or 5 mg/mL of DNP prior to injury. Twenty-four hours following surgery, mitochondrial function was assessed in mitochondria isolated from spinal cord synaptosomes. In addition, synaptosomes were used to measure indicators of reactive oxygen species formation, lipid peroxidation, and protein oxidation. Relative to vehicle-treated animals, pretreatment with DNP maintained mitochondrial bioenergetics and significantly decreased reactive oxygen species levels, lipid peroxidation, and protein carbonyl content following spinal cord injury. Furthermore, pretreatment with DNP significantly increased the amount of remaining white matter at the injury epicenter 6 weeks after injury. These results indicate that treatment with mitochondrial uncoupling agents may provide a novel approach for the treatment of secondary injury following spinal cord contusion.

Cyclooxygenase inhibition as a strategy to ameliorate brain injury

Cyclooxygenase (COX) is the obligate, rate-limiting enzyme for the conversion of arachidonic acid into prostaglandins. Two COX enzymes have been identified: a constitutively expressed COX-1 and an inducible, highly regulated COX-2. Widely used to treat chronic inflammatory disorders, COX inhibitors have shown promise in attenuating inflammation associated with brain injury. However, the use of COX inhibition in the treatment of brain injury has met with mixed success. This review summarizes our current understanding of COX expression in the central nervous system and the effects of COX inhibitors on brain injury. Three major targets for COX inhibition in the treatment brain injury have been identified. These are the cerebrovasculature, COX-2 expression by vulnerable neurons, and the neuroinflammatory response. Evidence suggests that given the right treatment paradigm, COX inhibition can influence each of these three targets. Drug interactions and general considerations for administrative paradigms are also discussed. Although therapies targeted to specific prostaglandin species, such as PGE2, might prove more ameliorative for brain injury, at the present time non-specific COX inhibitors and COX-2 specific inhibitors are readily available to researchers and clinicians. We believe that COX inhibition will be a useful, ameliorative adjunct in the treatment of most forms of brain injury.

Recovery after high-dose methylprednisolone and delayed evacuation: a case of spinal epidural hematoma

Spinal epidural hematoma (SEH) is rare and not without serious sequelae. We report a patient who developed Brown-Séquard syndrome from SEH after fluoroscopic-guided cervical steroid injection and favorable response to methylprednisolone (MP). A 56-year-old man reported immediate sharp shooting pain to the upper extremities on introduction of epidural toughy needle. A total of 5 mL of 0.2% ropivacaine and 120 mg methylprednisolone acetate suspension was administered at the C6-7 interspace. Within half an hour, a neurologic deficit occurred at C7-8 and right Brown-Séquard syndrome developed. Once SEH was suspected (3 hours after onset of neurologic deficit), a protocol of high-dose MP intravenous infusion was initiated. Immediate incomplete recovery of motor, sensory, and sphincteric functions was noted within 30 minutes of infusion. Emergency spinal C6-T2 bilateral decompressive laminectomies and evacuation SEH were performed within an expected delay (10 hours from the onset of neurologic deficit). Fluoroscopic guidance does not take the place of adherence to meticulous technique. An unexplained neurologic deficit after invasive spinal procedures should raise the concern for SEH. Early recognition and emergent evacuation remain the mainstay management for SEH. This case suggests some neuroprotection from MP in cases of cervicothoracic cord compression secondary to traumatic SEH. When potential risks for SEH exist, it is advisable not to administer local anesthetic so as not to interfere with neurologic assessment and delaying the diagnosis.

High-dose methylprednisolone treatment in experimental focal cerebral ischemia

Previous studies using steroids for experimental focal stroke have demonstrated conflicting results, possibly related to dose used or ischemic models employed. In this study we examined high-dose methylprednisolone treatment following permanent and temporary focal cerebral ischemia in the rat. Focal stroke was induced in spontaneously hypertensive rats by permanent right common carotid and either permanent or 3 h of temporary middle cerebral artery (MCA) occlusion. Methylprednisolone (105 mg/kg) was administered intra-arterially. Infarct volume was measured at 24 h after permanent and temporary MCA occlusion. Cerebral edema was determined by measuring right and left hemispheric volumes and water content 24 h after permanent MCA occlusion in one experiment. Methylprednisolone, whether administered in divided doses over 12 h (n = 15 in each group) or a single bolus (n = 9 per group), had no effect on infarct volume after permanent MCA occlusion. Methylprednisolone treatment also had no influence on cerebral edema (n = 9 per group). In two different experiments, methylprednisolone given in divided doses over 12 h (n = 11, n = 25) after temporary MCA occlusion decreased infarct volume (P < 0.05) by 20% compared with saline controls (n = 10, n = 25). High dose methylprednisolone decreased infarct volume following temporary, but not permanent, focal ischemia. The benefit suggests that high dose methylprednisolone may prove useful clinically if reperfusion can be established with thrombolytic agents. Furthermore, the differential treatment effect in the setting of comparable ischemic insults implies that different modifiable biochemical processes may be present during temporary but not permanent focal ischemia, thus providing indirect evidence for reperfusion injury.

Comparison of the effects of melatonin and methylprednisolone in experimental spinal cord injury

OBJECT

Melatonin is a very effective antioxidant agent. This study was performed to investigate the effects of melatonin in experimental spinal cord injury (SCI). The authors also compared its effects with those of methylprednisolone, which also protects the spinal cord from secondary injury because of its antioxidant effect on membrane lipids.

METHODS

Adult male albino rats were used for the study, and paraplegia was produced using a previously described weight-drop technique. Melatonin and methylprednisolone were given intraperitoneally by bolus injections of 100 mg/kg and 30 mg/kg, respectively, immediately after induction of trauma. The animals were killed, and 1-cm samples of injured spinal cord were obtained at 1, 24, and 48 hours postinjury. Lipid peroxidation was estimated by thiobarbituric acid test. Electron microscopic studies were performed to determine the effects of melatonin on neurons, axons, and subcellular organelles after experimental SCI. A grading system was used for quantitative evaluation. Following SCI, there was significant increase in lipid peroxidation. In melatonin- and methylprednisolone-treated groups, lipid peroxidation was found to decrease to the baseline (preinjury) levels. There was a significant difference between trauma-alone and treatment groups, but no statistical difference was found between the melatonin- and methylprednisolone-treated groups. Electron microscopic findings showed that SCI produced by the weight-drop technique resulted in profound tissue damage.

CONCLUSIONS

Both melatonin and methylprednisolone have been shown to protect neuron, axon, myelin, and intracellular organelles including mitochondrion and nucleus. However, this study provides quantitative evidence that this protection of neurons and subcellular organelles of spinal cord after secondary injury is much more obvious in melatonin-treated rats than those treated with methylprednisolone. In view of these data, melatonin has been shown to be very effective in protecting the injured spinal cord from secondary injury.

Effect of mexiletine on lipid peroxidation and early ultrastructural findings in experimental spinal cord injury

OBJECT

The purpose of this study was to investigate the effect of mexiletine on lipid peroxidation and on ultrastructural findings after induced spinal cord injury (SCI). The authors also compared the activity of mexiletine to that of the well-known antioxidant, methylprednisolone sodium succinate (MPSS).

METHODS

Wistar rats were divided into seven groups, (Groups 1-7). Those in Groups 1 and 2 were control animals that underwent laminectomy only, after which nontraumatized spinal cord samples were obtained immediately (Group 1) and 2 hours postsurgery (Group 2). Spinal cord injury was induced in all other groups, and cord samples were obtained at 2 hours postsurgery. The rats in Group 3 underwent SCI alone; those in Group 4 received 30 mg/kg of MPSS intraperitoneally immediately after trauma was induced; and those in Groups 5, 6, and 7 received 1, 10, and 50 mg/kg of mexiletine, respectively, by intraperitoneal injection immediately after trauma was induced. Compared with the levels in control animals, lipid peroxidation was significantly elevated in rats in Groups 3 and 5, but there were no statistical differences among those in Groups 1, 2, 4, 6 and 7 in this regard. Compared with the findings in rats in Group 3, ultrastructural damage post-SCI was minor in rats in Groups 4 and 5, and there was even less damage evident in rats in Group 7.

CONCLUSIONS

Analysis of these findings showed that administration of 50 mg/kg mexiletine significantly decreased the level of lipid peroxidation and protected spinal cord ultrastructure following SCI.

Methylprednisolone or tirilazad mesylate administration after acute spinal cord injury: 1-year follow up. Results of the third National Acute Spinal Cord Injury randomized controlled trial

OBJECT

A randomized double-blind clinical trial was conducted to compare neurological and functional recovery and morbidity and mortality rates 1 year after acute spinal cord injury in patients who had received a standard 24-hour methylprednisolone regimen (24MP) with those in whom an identical MP regimen had been delivered for 48 hours (48MP) or those who had received a 48-hour tirilazad mesylate (48TM) regimen.

METHODS

Patients for whom treatment was initiated within 3 hours of injury showed equal neurological and functional recovery in all three treatment groups. Patients for whom treatment was delayed more than 3 hours experienced diminished motor function recovery in the 24MP group, but those in the 48MP group showed greater 1-year motor recovery (recovery scores of 13.7 and 19, respectively, p=0.053). A greater percentage of patients improving three or more neurological grades was also observed in the 48MP group (p=0.073). In general, patients treated with 48TM recovered equally when compared with those who received 24MP treatments. A corresponding recovery in self care and sphincter control was seen but was not statistically significant. Mortality and morbidity rates at 1 year were similar in all groups.

CONCLUSIONS

For patients in whom MP therapy is initiated within 3 hours of injury, 24-hour maintenance is appropriate. Patients starting therapy 3 to 8 hours after injury should be maintained on the regimen for 48 hours unless there are complicating medical factors.

Methylprednisolone or tirilazad mesylate administration after acute spinal cord injury: 1-year follow up

Object

A randomized double-blind clinical trial was conducted to compare neurological and functional recovery and morbidity and mortality rates 1 year after acute spinal cord injury in patients who had received a standard 24-hour methylprednisolone regimen (24MP) with those in whom an identical MP regimen had been delivered for 48 hours (48MP) or those who had received a 48-hour tirilazad mesylate (48TM) regimen.

Methods

Patients for whom treatment was initiated within 3 hours of injury showed equal neurological and functional recovery in all three treatment groups. Patients for whom treatment was delayed more than 3 hours experienced diminished motor function recovery in the 24MP group, but those in the 48MP group showed greater 1-year motor recovery (recovery scores of 13.7 and 19, respectively, p = 0.053).A greater percentage of patients improving three or more neurological grades was also observed in the 48MP group (p = 0.073). In general, patients treated with 48TM recovered equally when compared with those who received 24MP treatments. A corresponding recovery in self care and sphincter control was seen but was not statistically significant. Mortality and morbidity rates at 1 year were similar in all groups.

Conclusions

For patients in whom MP therapy is initiated within 3 hours of injury, 24-hour maintenance is appropriate. Patients starting therapy 3 to 8 hours after injury should be maintained on the regimen for 48 hours unless there are complicating medical factors.

Methylprednisolone attenuates airway and vascular responses induced by reactive oxygen species in isolated, plasma-perfused rat lungs

The effects of methylprednisolone (MP) on the acute airway and pulmonary vascular responses induced by reactive oxygen species (ROS) were investigated in isolated, plasma-perfused rat lungs. ROS were generated by adding xanthine oxidase and hypoxanthine to the perfusate. MP was administered in 3 different ways: 1. Added to the perfusate (1 mg*ml-1) 5 min prior to xanthine oxidase and hypoxanthine, 2. Given as intraperitoneal injections (40 mg*kg-1) to lung donor rats 12 and 2 hours prior to the experiments, or 3. Combining 1 and 2. The lungs were perfused at constant volume inflow (15 ml*min-1). Pulmonary arterial pressure and transpulmonary pressure were followed for 30 min after addition of xanthine oxidase and hypoxanthine. ROS induced a powerful, acute broncho- and vasoconstriction, which was inhibited by addition of MP to the perfusate. Pretreatment with MP also inhibited the vascular and airway responses. Adding MP to the perfusate of pretreated lungs further reduced the ROS-induced smooth muscle constriction. In conclusion, MP inhibits vasoconstriction and bronchoconstriction induced by ROS in isolated rat lungs.

Effects of methylprednisolone on lesioned and uninjured mammalian spinal neurons: viability, ultrastructure, and network electrophysiology

An in vitro investigation was undertaken to provide information regarding the effectiveness of methylprednisolone sodium succinate (MPSS) as a treatment for the primary mechanical injury of spinal cord (SC) trauma. Exposure of uninjured mouse SC cells to MPSS for 24 h caused neuronal stress when the concentration exceeded 150 micrograms/mL; neuronal death occurred at concentrations above 600 micrograms/mL. The concentration range for MPSS protection of SC neurons subjected to a defined physical injury (laser microbeam transection of a primary dendrite 100 microns from the perikaryon) was very narrow: survival in the 30 micrograms/mL group differed significantly from the untreated control group (68.5% +/- 14.1 vs. 47.1% +/- 14.1), treatment with 20 or 60 micrograms/mL MPSS did not increase survival, and treatment with 100 micrograms/mL MPSS accelerated ultrastructural deterioration and increased the likelihood of death. Enhanced survival of lesioned neurons was observed when 30 micrograms/mL MPSS was applied within 15 min of dendrotomy but not when MPSS was administered 2 h after lesioning. Multimicroelectrode plate (MMEP) studies of SC network electrical activity indicated that MPSS associated readily with neuronal membranes. This finding was consistent with the hypothesis that MPSS may protect lesioned neurons by stabilizing damaged membranes, enhancing lesion resealing, and limiting the spread of ion-mediated damage. However, comparisons of neurite die-back 24 h after dendrotomy found no significant difference between MPSS-treated and control neurons. Application of 30 or 100 micrograms/mL MPSS increased the spontaneous burst activity of SC networks grown on MMEPs, however, there was no evidence that the increased excitability at these concentrations was the result of specific actions of MPSS on GABA or NMDA synapses.

Methylprednisolone reduces spontaneous nystagmus following unilateral labyrinthectomy in guinea pig

The present study investigated the effects of methylprednisolone on the vestibular compensation process following unilateral labyrinthectomy in guinea pigs. A single injection of methylprednisolone (15, 30 or 60 mg/kg s.c.), 15 min pre-labyrinthectomy, had no significant effect on either the severity or the rate of compensation of spontaneous ocular nystagmus or yaw head tilt; roll head tilt showed a significant change in the rate of compensation (P < 0.005), due to increased roll head tilt in the 60 mg/kg group. However, a pre-labyrinthectomy injection of 30 mg/kg s.c. methylprednisolone followed by a second 30 mg/kg injection at 4 h post-labyrinthectomy resulted in a significant reduction in spontaneous nystagmus frequency (P < 0.005) and a significant change in the rate of spontaneous nystagmus compensation (P < 0.005). The additional 30 mg/kg injection had no significant effect on the magnitude or compensation of the postural symptoms. These results indicate that, at the optimal dose of 30 mg/kg, 2 injections of methylprednisolone (15 min pre-labyrinthectomy and 4 h post-labyrinthectomy) result in a significant reduction in spontaneous nystagmus frequency.