The Effect of Ependymal Cell Transplantation on Nerve Regeneration after Spinal Cord Injury in Rats / 대한해부학회지

Nerve regeneration in the central nervous system has been studied by grafting various tissues and cells. Choroid plexus epithelial cells represent a continuation of ventricular ependymal cells and have the same origin as regarded as modified ependymal cells. To study the use of choroid plexus ependymal cell grafting for nerve regeneration in the spinal cord, the choroid plexus was excised from the lateral and fourth ventricles of adult Sprague-Dawley rats, minced into small fragments, and grafted at the T9 level in adult rat spinal cord transected or contused. In this study, transplants of choroid plexus ependymal cells were successfully used to promote functional and structural recovery after spinal cord transection and contusion. The area of damaged spinal cord was diminished after choroid plexus ependymal cells transplantation. Nearly normal anterior horn cells were observed immediately distal to the transected region. Tyrosine hydroxylase immunoreactive descending fibers were observed in the distal region beyond transected area. These findings indicate that choroid plexus ependymal cells have the ability to facilitate axonal growth, suggesting that they may be a promising candidate as graft for the promotion of nerve regeneration in the spinal cord.

Microscopic Changes of the Spinal Cord after the Intrathecal Administration of Ondansetron in the Rat / 대한마취과학회지

BACKGROUND: Serotonin type 3 receptors are abundant in the dorsal horn of the spinal cord and in the spinal tract of the trigeminal nerve in the medulla. Moreover, the intrathecal (IT) or epidural administration of ondansetron, a selective 5-hydroxytryptamine 3 (5-HT3) receptor antagonist, might prevent postoperative nausea, vomiting and intrathecal opioid-induced pruritus more effectively than the drug administered systemically. Before new drugs for spinal administration are accepted for clinical practice, experimental neurotoxicity studies must be undertaken. This study was performed in rats in order to reveal the behavioral and morphological signs of spinal cord damage after chronic IT ondansetron administration. METHODS: Rats were anesthetized using enflurane in oxygen and an 8 cm polyethylene catheter was advanced caudally through the atlanto-occipital membrane under aseptic surgical conditions. Twelve rats were randomly divided into two groups, an ondansetron (O) group (n = 6) and a normal saline (N) group (n = 6). After postoperative 7 days, we started the IT injection of ondansetron 40microgram (20microliter) or normal saline 20microliter once a day over two weeks. Potential changes of spinal cords were evaluated morphologically by light microscopy (LM) and electron microscopy (EM) in addition to behavioral changes. RESULTS: No rat in either groups showed any motor or behavioral changes during the administration of ondansetron. By LM and EM, all six rats in the O group showed massive neovascularization over the white and gray matters of spinal cords. CONCLUSIONS: The results suggest that chronic IT administration of ondansetron causes pathologic changes in the rat spinal cord.

Quantitative Analysis of Agmatine by HPLC in Ischemic Brain / 대한해부학회지

Agmatine, a widely distributed molecule in mammalian tissues, shows neuroprotective effects in brain ischemia. We describe the neuroprotective effects of agmatine in the mouse MCAO model and the quantitative change of agmatine in ischemic injury. Brain ischemic injured mice were injected with agmatine (100 mg/kg of mouse, IP). Agmatine significantly reduced the infarct area after MCAO. Despite the similar patterns of agmatine change observed in control or agmatine injected animals, the agmatine levels of the penumbra were significantly higher than those of the striatum and the cerebral cortex during the early period (<1 hour after 2 hours of MCA occlusion). This suggests that the early period, during which agmatine levels increase in the brain, is the crucial period in terms of neuroprotective effect during ischemia.

Influences of GST Subfamily & NQO1 Gene Polymorphism on the Metabolism of Benzene / 대한해부학회지

The higher concentration of traces of aromatic hydrocarbons prevailing in the refinery atmosphere causes severe occupational health hazard to refinery workers. In this study, the biochemical role of genetic polymorphism in modulating urinary excretion of benzene metabolite as phenol level has been investigated in 90 workers exposed to benzene in the petroleum refinery plants of Korea. Glutathione S-transferase (GST) subfamily as GSTM1, GSTT1 and GSTP1 and NAD(P)H: quinone oxidoreductase 1 (NQO1) gene polymorphisms were determined by polymerase chain reaction (PCR)-based methods. The mean concentration of volatile benzene in the refinery environment was 0.042 mg/m(3) (SD, 0.069) and that of urinary phenol was 7.42 mg/g creatinine (SD, 11.3). The airborne benzene concentration was significantly related to the concentration of phenol in urine (r = 0.640, p<0.01). However, all the genotypes of GST subfamily and NQO1 except small sample size of genotypes in GSTM1 and GSTT1 none of them were higher than that of present genotype. Also, it was higher in the GSTP1*1/*1 than in the GSTP1*1/*2. The various biological (i.e. age and liver function parameters) or lifestyle factors (i.e. medication, smoking, alcohol and coffee intake), also taken into account as potential confounders, did not influence the correlations found. These results suggested that GST subfamily and NQO1 genotypes might play an important role in the metabolism of benzene.