• Journal of Korean Neurosurgical Society
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• v.29 no.9
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• pp.1153-1160
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• 2000

Objectives : This study was undertaken to investigate the effect of noncompetitive NMDA receptor blocker, MK801 on motor recovery, SSEP and pathology in spinal cord injured rat. Methods : The effects of MK801 on neuronal function protection, SSEP, and pathology were measured on spinal cord injury rats which were divided into 6 groups according to dose, time of drug delivery and magnitude of injury. Spinal cord injury was made with the magnitude of 25gm-cm and 50gm-cm on 42 rats. BBB locomotor function test was performed to evaluate the motor power recovery in hindlimb for 2 weeks after injury. After motor function test was completed, SSEP was measured. Amplitude and latency of the P1, N1 peak was measured and compared between groups. Finally rats were sacrificed, and pathologic findings including measurement of area of necrotic cord were studied and compared between groups. Results : Motor recovery at 2 weeks was better in MK801 group comparing to saline control group. SSEP at 2 weeks showed no difference in N1, P1 latencies, but significantly greater amplitude in MK801 group, compared to saline control group. On light microscope, there was no specific histologic differences between experimental groups. The cystic necrotic area in coronal plane was measured and compared in each group. The necrotic area was significantly smaller in MK801 1mg/kg group(delivered after injury) than vehicle group. The necrotic area in MK801 5mg/kg group and MK801 1mg/kg group(delivered before injury) was smaller than vehicle group even though it was not statistically significant. Conclusion : From the above result, it is speculated that NMDA blocker, MK801 can improve impaired neuronal function in spinal cord injury.

• Korean Journal of Veterinary Research
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• v.43 no.1
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• pp.57-66
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• 2003

Single and 28-day repeated dose toxicity studies of botulimnn toxin type A were carried out in ICR mice and Sprague-Dawley rats, respectively. In the single dose toxicity study, botulinwn toxin was injected intraperitoneally to male and female mice at a single dose of 40, 59, 89 133 and 200 ng/10 ml saline/kg. All animals died from 59 ng/kg group. Some clinical signs, such as decrease in locomotor activity, dyspnea, prone position and ptosis, were observed in most of both sexes from 59 ng/kg group, but no signs were seen in all animals at 40 ng/kg group. The results showed that the median lethal dose of botulinum toxin might be in the range of 40-59 ng/kg in both sexes. In the repeated dose toxicity study, the test material was administered intradermally for 28 days at doses of 0 (vehicle-treated control), 1.25, 2.5, 5.0 and $10.0ng/head/50{\mu}{\ell}$ saline in male and female rats. No test material-related changes were noted in survivals, clinical signs, food and water consumptions and gross finding in any group. Botulinum toxin treatment significantly decreased the body weight gain rate in male of 5.0 ng/head group and over and in female of 10.0 ng/head group compared to vehicle-treated control. One or more relative organ weights (i.e., spleen, thymus, liver and kidney) were increased significantly from 5.0 ng/head group compared to vehicle-treated control in both sexes. Serum biochemistry revealed increases in aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine phosphokinase, total protein and albumin in male, and increases in AST and ALT and decreases in $K^+$ and $Cl^-$ in female without dose-pendent manners. In the histopathological study, physical stimulation by needle caused slight inflammations of dennis. In addition, botulinum toxin treatment induced denervation of nerve cell and disuse of muscle, resulting in atrophy of skeletal muscle in both sexes from 2.5 ng/head group. When the antibodies to toxin were determined in all animals, a significant increase in serum antibodies was observed from 5.0 ng/head group. The results showed that the NOAEL of botulinum toxin might be 1.25 ng/head for 28-day repeated dose toxicity in rats.

• Herbal Formula Science
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• v.25 no.4
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• pp.483-497
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• 2017

Background : Behavioral stress has been suggested as one of the significant factors that is able to disrupt physiological systems and cause depression as well as changes in various body systems. The stressful events can alter cognition, learning, memory and emotional responses, resulting in mental disorders such as depression and anxiety. Results : We used a restraint stress model to evaluate the alteration of behavior and stress-related blood parameter. The animals were randomly divided into two groups of five animals each group. Furthermore, we assessed the change of body weight to evaluate the locomotor activity as well as status of emotional and anxiety in mice. After 7 days of restraint stress, the body weight had significantly decreased in the restraint stress group compared with the control group. We also observed stress-associated behavioral alterations, as there was a significant decrease in open field and forced swim test, whereas the immobilization time was significantly increased in the stress group compared to the control group. We observed the morphological changes of neuronal death and microglia by immunohistochemistry and western blot. In our study restraint stress did not cause change in neuronal cell density in the frontal cortex and CA1 hippocampus region, but there was a trend for an increased COX-2 and iNOS protein expression and microglia (CD11b) in brain, which is restraint stress. Conclusion : Our study, there were significant alterations observed in the behavioral studies. We found that mice undergoing restraint stress changed behavior, confirming the increased expression of inflammatory factors in the brain.

• Biomolecules & Therapeutics
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• v.23 no.6
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• pp.597-603
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• 2015

Synthetic cannabinoids JWH-018 and JWH-250 in 'herbal incense' also called 'spice' were first introduced in many countries. Numerous synthetic cannabinoids with similar chemical structures emerged simultaneously and suddenly. Currently there are not sufficient data on their adverse effects including neurotoxicity. There are only anecdotal reports that suggest their toxicity. In the present study, we evaluated the neurotoxicity of two synthetic cannabinoids (JWH-081 and JWH-210) through observation of various behavioral changes and analysis of histopathological changes using experimental mice with various doses (0.1, 1, 5 mg/kg). In functional observation battery (FOB) test, animals treated with 5 mg/kg of JWH-081 or JWH-210 showed traction and tremor. Their locomotor activities and rotarod retention time were significantly (p<0.05) decreased. However, no significant change was observed in learning or memory function. In histopathological analysis, neural cells of the animals treated with the high dose (5 mg/kg) of JWH-081 or JWH-210 showed distorted nuclei and nucleus membranes in the core shell of nucleus accumbens, suggesting neurotoxicity. Our results suggest that JWH-081 and JWH-210 may be neurotoxic substances through changing neuronal cell damages, especially in the core shell part of nucleus accumbens. To confirm our findings, further studies are needed in the future.

• Toxicological Research
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• v.20 no.1
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• pp.83-88
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• 2004

The present study was carried out to investigate the potential adverse effects of CKD-602 by a 5-day repeated intravenous dose in Sprague-Dawley rats. The test article, CKD-602, was administered intravenously to male and female rats at dose levels of 0.07, 0.22, 0.67, 2.0 and 6.0 mg/kg/day for 5 days consecutively. Mortalities, clinical findings, and body weight changes were monitored for the 14-day period after cessation of the administration. At the end of 14-day observation period, all animals were sacrificed and complete gross postmortem examinations were performed. There were 2 and 5 treatment related deaths in the 0.67 and 2.0 mg/kg/day dose groups of both genders, respectively. Treatment related clinical signs, including hair loss, skin paleness, decreased locomotor activity, emaciation, and changes in stool were observed in a dose-dependent manner from the third day after initiation of the injection. Decrease or suppression of body weight was also observed dose-dependently in males and females of the treated groups. Gross postmortem examinations revealed a dose-dependent increase in the incidence and severity of atrophy or hypertrophy and white membrane formation in the spleen, atrophy of the thymus, diffuse white spots and paleness of the liver, paleness of the lung, kidney and adrenal gland, and dark red discoloration and dark red contents in the alimentary tract. Based on these results, it was concluded that the 5-repeated intravenous injection of CKD-602 to male and female rats resulted in increased incidence of abnormal clinical signs and death, decreased or suppressed body weight, and increased incidence of abnormal gross findings. In the present experimental conditions, the $LD_{50}$ value was 2.07 (95% confidence limit not specified) mg/kg/day in both genders and the $LD_{10}$ value was 1.72 (95% confidence limit not specified) mg/kg/day in both genders.

• Journal of Life Science
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• v.14 no.4
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• pp.547-552
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• 2004

The present study was carried out to investigate the potential acute toxicity of amitraz by a single subcutaneous dose in beagle dogs. The test chemical was administered subcutaneously to male beagle dogs at dose levels of 0, 2, 10, or 50 mg/kg. Mortalities, clinical findings, and body weight changes were monitored for the 14-day period following the administration. At the end of 14-day observation period, hematology, serum biochemistry, and gross postmortem examinations were examined. A single dog in the 50 mg/kg group was found dead on day 3 after treatment and the other two dogs in the group were sacrificed because of the severe clinical signs on day 7 after treatment. Treatment related clinical signs, including anorexia, edema, mass and abscess formation in the injection sites, depression, vomiting, lacrimation, decreased locomotor activity, ataxia, recumbency, paresis in the limbs, and/or moribundity were observed in all treatment groups in a dose-dependent manner. Decreased or suppressed body weight gain was also observed dose-dependently in all treated groups. In autopsy, dead animals in the 50 mg/kg group showed muscular hemorrhage and inflammation in the injection sites and congestion in the liver and kidney. The terminal sacrificed animals in the 10 mg/kg group also exhibited muscular hemorrhage and inflammation in the injection sites. Whereas, no treatment related effects on hematology and serum biochemistry were observed on day 14 after treatment at any dose tested. On the basis of the results, it was concluded that a single subcutaneous injection of amitraz to beagle dogs resulted in increased incidence of abnormal clinical signs and death, decreased body weight, and increased incidence of abnormal gross findings. In the experimental conditions, the $LD_{50}$value of amitraz was 22.3 mg/kg (95% confidence limit not specified) and the no-observed-adverse-effect level (NOAEL) was considered to be below 2 mg/kg for male dogs.

• Biomolecules & Therapeutics
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• v.11 no.4
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• pp.249-256
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• 2003

Pyroligneous liquid(PL) is produced by carbonizing Oak in 350-40$0^{\circ}C$. It is traditionally used for treating stress-related disorder, hepatic disease, immune disorder, G-I disorder and inflammatory disease. The aim of this study is to investigate anti-stress effects of PL. The experiments were performed with the use of young(9 weeks of age) male rats of SD strain and the male ICR mice (20-25 g). Animals of the normal group were not exposed to any stress and the control group were exposed to stress. The rats of the Ginseng, diazepam(BZ) and PL supplementary group were orally administered once a day 100 g of Ginseng extract-kg body weight, 5 mg of BZ/kg body weight and 1 ml of PL100 g body weight and then exposed to stress. The mice of the Ginseng, BZ and PL supplementary group were given water containing 100 g of Ginseng extract/100 ml potable water, 5 mg of BZ/kg 100 ml of drinking water and 10 ml of PL/100 ml of drinking water and exposed to stress. Animals were given materials for 7 days after stabilizing them, and then were given supplementary materials for 5 days with stress. They were stressed by immobilization for 30 minutes and then the animals were exposed to electroshocks for 5 minutes. We recorded stress-related behavioral changes of experimental animals by stressing them using the Etho-vision system and measured the levels of corticosterone in blood While stress suppressed locomotor activity of animals, PL-supplementation partially blocked the stress effect of locomotion in rats and mice, and also partially blocked stress-induced behavioral changes such as freezing, burrowing, smelling and rearing activity in rats and freezing, grooming, tailing and rearing in mice. The staying time of stressed rats and mice in open area decreased and in closed area it increased relatively in elevated plus maze test. However, these changes also partially were blocked by PL-supplementation. PL-supplementation decreased levels of blood corticosterone increased by stress in rats. These results suggest that PL protects partially the living organism from stress attack in some cases.

• Journal of Korean Neurosurgical Society
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• v.64 no.5
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• pp.705-715
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• 2021

Objective : Through our previous clinical trials, the demonstrated therapeutic effects of MSC in chronic spinal cord injury (SCI) were found to be not sufficient. Therefore, the need to develop stem cell agent with enhanced efficacy is increased. We transplanted enhanced Wnt3-asecreting human mesenchymal stem cells (hMSC) into injured spines at 6 weeks after SCI to improve axonal regeneration in a rat model of chronic SCI. We hypothesized that enhanced Wnt3a protein expression could augment neuro-regeneration after SCI. Methods : Thirty-six Sprague-Dawley rats were injured using an Infinite Horizon (IH) impactor at the T9-10 vertebrae and separated into five groups : 1) phosphate-buffered saline injection (injury only group, n=7); 2) hMSC transplantation (MSC, n=7); 3) hMSC transfected with pLenti vector (without Wnt3a gene) transplantation (pLenti-MSC, n=7); 4) hMSC transfected with Wnt3a gene transplantation (Wnt3a-MSC, n=7); and 5) hMSC transfected with enhanced Wnt3a gene (1.7 fold Wnt3a mRNA expression) transplantation (1.7 Wnt3a-MSC, n=8). Six weeks after SCI, each 5×10⁵ cells/15 µL at 2 points were injected using stereotactic and microsyringe pump. To evaluate functional recovery from SCI, rats underwent Basso-Beattie-Bresnahan (BBB) locomotor test on the first, second, and third days post-injury and then weekly for 14 weeks. Axonal regeneration was assessed using growth-associated protein 43 (GAP43), microtubule-associated protein 2 (MAP2), and neurofilament (NF) immunostaining. Results : Fourteen weeks after injury (8 weeks after transplantation), BBB score of the 1.7 Wnt3a-MSC group (15.0±0.28) was significantly higher than that of the injury only (10.0±0.48), MSC (12.57±0.48), pLenti-MSC (12.42±0.48), and Wnt3a-MSC (13.71±0.61) groups (p<0.05). Immunostaining revealed increased expression of axonal regeneration markers GAP43, MAP2, and NF in the Wnt3a-MSC and 1.7 Wnt3a-MSC groups. Conclusion : Our results showed that enhanced gene expression of Wnt3a in hMSC can potentiate axonal regeneration and improve functional recovery in a rat model of chronic SCI.

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