• Journal of Korean Neurosurgical Society
• /
• v.50 no.4
• /
• pp.288-292
• /
• 2011

Objective : Matrix metalloproteinases (MMPs), especially MMP-2 and MMP-9 have been known to play an important role in secondary inflammatory reaction after spinal cord injury (SCI). The aim of this study was to investigate the expression and activity of MMP-2 and MMP-9 and to determine their relationship with disruption of endothelial blood-barrier after photochemically induced SCI in rats. Methods : Female Sprague-Dawley rats, weighing between 250 and 300 g (aged 8 weeks) received focal spinal cord ischemia by photothrombosis using Rose Bengal. Expressions and activities of MMP-2 and MMP-9 were assessed by Western blot and gelatin zymography at various times from 6 h to 7 days. Endothelial blood-barrier integrity was assessed indirectly using spinal cord water content. Results : Zymography and Western blot analysis demonstrated rapid up-regulation of MMP-9 protein levels in spinal cord after ischemic onset. Expressions and activities of MMP-9 showed a significant increased at 6 h after the photothrombotic ischemic event, and reached a maximum level at 24 h after the insult. By contrast, activated MMP-2 was not detected at any time point in either the experimental or the control groups. When compared with the control group, a significant increase in spinal cord water content was detected in rats at 24 h after photothrombotic SCI. Conclusion : Early up-regulation of MMP-9 might be correlated with increased water content in the spinal cord at 24 h after SCI in rats. Results of this study suggest that MMP-9 is the key factor involved in disruption of the endothelial blood-barrier of the spinal cord and subsequent secondary damage after photothrombotic SCI in rats.

• Journal of Chest Surgery
• /
• v.34 no.11
• /
• pp.823-830
• /
• 2001

Background: Paraplegia is a serious complication of thoracic or thoracoabdominal aortic operations, which is related to ischemic injury of the spinal cord induced by low perfusion pressure during cross clamping of the aorta. Ischemic preconditioning of heart or brain with reversible sublethal ischemic injury induces resistance to subsequent lethal ischemia. The aim of this study is to investigate whether ischemic tolerance could be induced by the preconditioning of the spinal cord using swine model. Material and Method: The animals were randomly assigned to three groups: sham group(n=3), control group(n=6) and pre-conditioning group(n=8). In the sham group, we performed the left thoracotomy only without any ischemic injury. In the preconditioning group, the swine received reversible spinal cord ischemic injury by aortic clamping for 20 minutes, whereas control group had no previous aortic cross- clamping. Forty-eight hours later, the aorta was clamped for 30 minutes in both groups. Neurological examination was done 24 hours later, then the animals were euthanized for histopathology and malonedialdehyde(MDA) spectrophotometry assay of the spinal cord. Result: Statistically significant difference in neurological outcome was observed between the control and preconditioning groups at 24 hours after ischemic injury. The incidence of paraplegia and severe paresis was 100% in the control group, and 62.5% in the preconditing group(p=0.028). There was no statistically significant difference in histopathology and MDA assay of the ischemic spinal cord between these two groups with borderline statistical difference in MDA assay(p=0.0745). Conclusion: In the present swine study, ischemic preconditioning could induce tolerance against 30 minute ischemic insult of the spinal cord, although the animals did not completely recover(stand-up or walk). We expect that combining this preconditioning with other currently existing protection methods might lead to a synergistic effect, which warrants further investigation.

• Biomolecules & Therapeutics
• /
• v.24 no.5
• /
• pp.495-500
• /
• 2016

This study aimed to explore the neuroprotection and mechanism of isoflurane on rats with spinal cord ischemic injury. Total 40 adult male Sprague-Dawley rats were divided into the four groups (n=10). Group A was sham-operation group; group B was ischemia group; group C was isoflurane preconditioning group; group D was isoflurane preconditioning followed by ischemia treatment group. Then the expressions of TWIK-related $K^+$ channel 1 (TREK1) in the four groups were detected by immunofluorescent assay, real time-polymerase chain reactions (RT-PCR) and western blot. The primary neurons of rats were isolated and cultured under normal and hypoxic conditions. Besides, the neurons under two conditions were transfected with green fluorescent protein (GFP)-TREK1 and lentivirual to overexpress and silence TREK1. Additionally, the neurons were treated with isoflurane or not. Then caspase-3 activity and cell cycle of neurons under normal and hypoxic conditions were detected. Furthermore, nicotinamide adenine dinucleotide hydrate (NADH) was detected using NAD+/NADH quantification colorimetric kit. Results showed that the mRNA and protein expressions of TREK1 increased significantly in group C and D. In neurons, when TREK1 silenced, isoflurane treatment improved the caspase-3 activity. In hypoxic condition, the caspase-3 activity and sub-G1 cell percentage significantly increased, however, when TREK1 overexpressed the caspase-3 activity and sub-G1 cell percentage decreased significantly. Furthermore, both isoflurane treatment and overexpression of TREK1 significantly decreased NADH. In conclusion, isoflurane-induced neuroprotection in spinal cord ischemic injury may be associated with the up-regulation of TREK1.

• The Korean Journal of Physiology
• /
• v.30 no.2
• /
• pp.289-297
• /
• 1996

Excitatory amino acids (EAA) are thought to play an important role in producing cell death associated with ischemic and traumatic spinal cord injury. The present study was carried out to determine if the response characteristics of spinal sensory neurons in segments adjacent to degeneration sites induced by EAA are altered following these morphological changes. Intraspinal injections of quisqualic acid (QA) produced neuronal degeneration and spinal cavitation of gray matter. The severity of lesions was significantly attenuated by pretreatment with a non-NMDA antagonist NBQX. In extracellular single unit recordings, dorsal horn neurons in QA injected animal showed the increased mechanosensitivity, which included a shift to the left in the stimulus-response relationship, an increased background activity and an increase in the duration of after-discharge responses. Neuronal responses, especially the C-fiber response, to suprathreshold electrical stimulation of sciatic nerve also increased in most cases. These results suggest that altered functional states of neurons may be responsible for sensory abnormalities, e.g. allodynia and hyperalgesia, associated with syringomyolia and spinal cord injury.

• Journal of Korean Neurosurgical Society
• /
• v.57 no.6
• /
• pp.445-454
• /
• 2015

Objective : In the present study we analyzed neuroprotective and antiapoptotic effect of the difumarate salt S-15176, as an anti-ischemic, an antioxidant and a stabilizer of mitochondrial membrane in secondary damage following spinal cord injury (SCI) in a rat model. Methods : Three groups were performed with 30 Wistar rats; control (1), trauma (2), and a trauma+S-15176 (10 mg/kg i.p., dimethyl sulfoxide) treatment (3). SCI was performed at the thoracic level using the weight-drop technique. Spinal cord tissues were collected following intracardiac perfusion in 3rd and 7th days of posttrauma. Hematoxylin and eosin staining for histopatology, terminal deoxynucleotidyl transferase dUTP nick end labeling assay for apoptotic cells and immunohistochemistry for proapoptotic cytochrome-c, Bax and caspase 9 were performed to all groups. Functional recovery test were applied to each group in 3rd and 7th days following SCI. Results : In trauma group, edematous regions, diffuse hemorrhage, necrosis, leukocyte infiltration and severe degeneration in motor neurons were observed prominently in gray matter. The number of apoptotic cells was significantly higher (p<0.05) than control group. In the S-15176-treated groups, apoptotic cell number in 3rd and 7th days (p<0.001), also cytochrome-c (p<0.001), Bax (p<0.001) and caspase 9 immunoreactive cells (p<0.001) were significantly decreased in number compared to trauma groups. Hemorrhage and edema in the focal areas were also noticed in gray matter of treatment groups. Results of the locomotor test were significantly increased in treatment group (p<0.05) when compared to trauma groups. Conclusion : We suggest that difumarate salt S-15176 prevents mitochondrial pathways of apoptosis and protects spinal cord from secondary injury and helps to preserve motor function following SCI in rats.

• Journal of Korean Neurosurgical Society
• /
• v.46 no.5
• /
• pp.479-483
• /
• 2009

Objective : A mouse model of spinal cord injury (SCI) could further increase our basic understanding of the mechanisms involved in injury and repair of the nervous system. The purpose of this study was to investigate whether methods used to produce and evaluate photochemical graded ischemic SCI in rats, could be successfully adapted to mice, in a reliable and reproducible manner. Methods : Thirty female imprinting control region mice (weighting 25-30 g, 8 weeks of age) were used in this study. Following intraperitoneal injection of Rose bengal, the translucent dorsal surface of the T8-T9 vertebral laminae of the mice were illuminated with a fiber optic bundle of a cold light source. The mice were divided into three groups; Group 1 (20 mg/kg Rose bengal, 5 minutes illumination), Group 2 (20 mg/kg Rose bengal, 10 minutes illumination), and Group 3 (40 mg/kg Rose bengal, 10 minutes illumination). The locomotor function, according to the Basso-Beattie-Bresnahan scale, was assessed at three days after the injury and then once per week for four weeks. The animals were sacrificed at 28 days after the injury, and the histopathology of the lesions was assessed. Results : The mice in group 1 had no hindlimb movement until seven days after the injury. Most mice had later recovery with movement in more than two joints at 28 days after injury. There was limited recovery of one joint, with only slight movement, for the mice in groups 2 and 3. The histopathology showed that the mice in group 1 had a cystic cavity involving the dorsal and partial involvement of the dorsolateral funiculi. A larger cavity, involving the dorsal, dorsolateral funiculi and the gray matter of the dorsal and ventral horns was found in group 2. In group 3, most of the spinal cord was destroyed and only a thin rim of tissue remained. Conclusion : The results of this study show that the photochemical graded ischemic SCI model. described in rats, can be successfully adapted to mice, in a reliable and reproducible manner. The functional deficits are correlated an increase in the irradiation time and, therefore, to the severity of the injury. The photothrombotic model of SCI, in mice with 20 mg/kg Rose bengal for 5 minutes illumination, provides an effective model that could be used in future research. This photochemical model can be used for investigating secondary responses associated with traumatic SCI.

• Journal of Chest Surgery
• /
• v.41 no.4
• /
• pp.405-416
• /
• 2008

Background: Spinal cord ischemic injury during thoracic and thoracoabdominal aortic surgeries remains a potentially devastating outcome despite using various methods of protection. Neuronal voltage-dependent sodium channel antagonists are known to provide neuroprotection in cerebral ischemic models. This study was designed to compare the neuroprotective effects of phenytoin with those of hypothermia in a rabbit model of spinal cord ischemia. Material and Method: Spinal cord ischemia was induced in New Zealand white rabbits by means of infrarenal aortic cross clamping for 25 minutes. Four groups of 8 animals each were studied. The control group and the hypothermia group received retrograde infusion of saline only ($22^{\circ}C$, 2 mL/min); the normothermic phenytoin group and the hypothermicphenytoin group received retrograde infusion of 100 mg of phenytoin at different rectal temperatures ($39^{\circ}C$ and $37^{\circ}C$, respectively) during the ischemic period. The neurologic function was assessed at 24 and 72 hours after the operation with using the modified Tarlov criteria. The spinal cords were harvested after the final neurologic examination for histopathological examination to objectively quantify the amount of neuronal damage. Result: No major adverse effects were observed with the retrograde phenytoin infusion during the aortic ischemic period. All the control rabbits became severely paraplegic, Both the phenytoin group and the hypothermia group had a better neurological status than did the control group (p < 0.05). The typical morphological changes that are characteristic of neuronal necrosis in the gray matter of the control animals were demonstrated by means of the histopathological examination, whereas phenytoin or hypothermia prevented or attenuated these necrotic phenomena (p < 0.05). The number of motor neuron cells positive for TUNEL staining was significantly reduced, to a similar extent, in the rabbits treated with phenytoin or hypothermia. Phenytoin and hypothermia had some additive neuroprotective effect, but there was no statistical significance between the two on the neurological and histopathological analysis. Conclusion: The neurological and histopathological analysis consistently demonstrated that both phenytoin and hypothermia may afford significant spinal cord protection to a similar extent during spinal cord ischemia in rabbits, although no significant additive effects were noticed.

• The Korean Journal of Pain
• /
• v.10 no.2
• /
• pp.304-307
• /
• 1997

Continuous epidural infusion, a combination of local anesthetic and opioid, have been widely administered for treatment of chronic cancer pain. A serious complications of epidural block is paraplegia which can also be caused by : direct spinal cord injury, epidural hematoma, epidural abscess, ischemic change, neurotoxicity, preexisting disease. Continuous epidural block for pain control of patient with cervical cancer was performed at $T_{12}/L_1$ interspace. A 4 cm catheter was inserted cephalad into the epidural space. After four months, back pain and motor weariless of lower extremities progressively developed. Spine CT showed bony destruction and soft mass-like lesion at $T_9$ & $T_{12}$ spine. We propose paraplegia was caused by spinal cord compression which resulted from vertebral metastasis of cervical cancer.

• The Korean Journal of Pharmacology
• /
• v.31 no.1 s.57
• /
• pp.1-9
• /
• 1995

The slow development of histopathological changes and long period required for stabilization of lesions have suggested that secondary injury processes exacerbate the effect of initial mechanical insult after traumatic spinal cord injury (SCI). The importance of glutamate receptors in the normal functions of spinal cord, in concert with the large body of evidence that points to their involvement in neurotoxicity due to both ischemic and traumatic insults to the CNS, suggested a probable role of glutamate receptors in secondary injury process after traumatic SCI. In order to investigate the involvement of excitatory amino acid in the secondary injury process after SCI, this study examined the effect of dextrorphan, a noncompetitive NMDA receptor antagonist, on the recovery of hindlimb function and the residual tissue at injury site following SCI. Locomotor function was assessed using open field test (21 point scale). At 8 weeks spinal cord tissue was examined using quantitative histopathologic technique. Prior to surgery female Long-Evans rats were adapted to the test environment. Rats received laminectomies (T9/T10), and spinal cord contusions (NYU impactor) were produced by a 10 gm weight dropped 25 mm. DXT (15 or 30 mg/kg, i.p.) or saline was injected 15 min before contusion. Behavioral testing resumed 2 days post-injury and continued twice a week for 8 weeks. No differences between DXT and saline groups were found for hindlimb function and sparing tissue at the lesion site. These results suggest that NMDA receptor might not be involved in secondary injury processes after traumatic SCI.

• Journal of Chest Surgery
• /
• v.35 no.4
• /
• pp.255-260
• /
• 2002

Paraplegia remains unresolved as the most dreaded operative complication with surgical treatment of descending thoracic and thoracoabdominal aortic diseases. In this study, the neuroprotective effect of trimetazidine that has been used clinically for ischemic heart disease was investigated in a rabbit spinal cord ischemia model. Material and Method: Thirty-three New Zealand white rabbits were randomized as follows: control group undergoing abdominal aortic occlusion but receiving no pharmacologic intervention(Group 1, n= 17); TMZ group(Group 2, n= 16) receiving 3 mg/kg trimetazidine intravenously before the occlusion of the aorta. Ischemia was induced by clamping the abdominal aorta just distal to the left renal artery for 30 minutes. Neurologic status was assessed at 2, 24, and 48 hours after the operation according to the modified Tarlov scale, then the lumbosacral spinal cord was processed for histopathologic examinations 48 hours after the final assessment. Result: The average motor function score was significantly higher in the TMZ group(3.20 $\pm$ 0.77 vs 1.13 $\pm$ 1.25 at 2 hours, 3.50 $\pm$ 0.76 vs 1.45 $\pm$ 1.57 at 24 hours, and 3.91 $\pm$ 0.30 vs 1.86 $\pm$ 1.86 at 48 hours after operation; p value$\leq$0.05). Histologic observations were correlated with the motor scores. Conclusion: The results suggested that trimetazidine reduced spinal cord injury during aortic clamping and that it may have clinical utility for the thoracoabdominal aortic surgery: