Neuregulin 1/ErbB4 signaling attenuates neuronal cell damage under oxygen-glucose deprivation in primary hippocampal neurons / 대한해부학회지

Neuregulin-1 Protects Neuronal Cells Against Damage due to CoCl2-Induced Hypoxia by Suppressing Hypoxia-Inducible Factor-1α and P53 in SH-SY5Y Cells / 대한배뇨장애요실금학회지

PURPOSE@#Hypoxia-mediated neurotoxicity contributes to various neurodegenerative disorders, including Alzheimer disease. Neuregulin-1 (NRG1) plays an important role in the development and plasticity of the brain. The aim of the present study was to investigate the neuroprotective effect and the regulating hypoxic inducible factor of NRG1 in cobalt chloride (CoCl₂) induced hypoxia.@*METHODS@#Hypoxia was induced in SH-SY5Y cells by CoCl₂ treatment. SH-SY5Y cells were pretreated with NRG1 and then treated with CoCl₂. Western blotting, immunocytochemistry, and lactate dehydrogenase (LDH) release assays were performed to examine neuroprotective properties of NRG1 in SH-SY5Y cells.@*RESULTS@#Our data showed that CoCl₂ induced cytotoxicity and changes of hypoxia-inducible factor-1α (HIF-1α) and p53 expression in SH-SY5Y cells. However, pretreatment with NRG1 inhibited CoCl₂-induced accumulation of HIF-1α and p53 stability. In addition, NRG1 significantly attenuated cell death of SH-SY5Y induced by CoCl₂.@*CONCLUSIONS@#NRG1 can regulate HIF-1α and p53 to protect neurons against hypoxic damage.

Evidence of early involvement of apoptosis inducing factor-induced neuronal death in Alzheimer brain / 대한해부학회지

Apoptosis inducing factor (AIF) has been proposed to act as a putative reactive oxygen species scavenger in mitochondria. When apoptotic cell death is triggered, AIF translocates to the nucleus, where it leads to nuclear chromatin condensation and large-scale DNA fragmentation which result in caspase-independent neuronal death. We performed this study to investigate the possibility that, in addition to caspase-dependent neuronal death, AIF induced neuronal death could be a cause of neuronal death in Alzheimer's disease (AD). We have found that AIF immunoreactivity was increased in the hippocampal pyramidal neurons in the Alzheimer brains compared to those of healthy, age-matched control brains. Nuclear AIF immunoreactivity was detected in the apoptotic pyramidal CA1 neurons at the early stage of AD and CA2 at the advanced stage. Nuclear AIF positive neurons were also observed in the amygdala and cholinergic neurons of the basal forebrain (BFCN) from the early stages of AD. The results of this study imply that AIF-induced apoptosis may contribute to neuronal death within the hippocampus, amygdala, and BFCN in early of AD.

Comparative Study of the L5 Spinal Nerve Transection Model and Sciatic Nerve Axotomy Model as a Peripheral Nerve Injury Model in Rat / 체질인류학회지

The aim of this study was to propose new more reliable peripheral nerve transection model to overcome the defect of the traditional sciatic axotomy model by specifically transecting L5 spinal nerve just after emerging from the intervertebral foramen and confining analysis area to the L5 spinal segment. The adult male Sprague-Dawley rats, weighing 300~350 g at the time of surgery, were used for the experiments. Four different experimental groups were used. 1. Sciatic nerve transection (Sc-Tx) group: transect the sciatic nerve in the popliteal fossa where it divided into the common peroneal nerve and tibial nerve. 2. L5 spinal nerve transection (L5-Tx) group: L5 spinal nerve was specifically transected. 3. Suture (Su) group: L5 spinal nerve was transected and immediately sutured. 4. Control group: the same surgical procedure with L5 spinal nerve transection group was performed except for the excision of L5 spinal nerve. To distinguish L5 motoneurons from the other level ones, the animals were received the retrograde tracer, FluoroGold into the axotomized proximal nerve stump. Serial coronal frozen sections at 40 microm thick through the L4 to L6 spinal segment was performed and the resultant total number of sections was about 180. Approximate serial 50 sections (approximately 2 mm) could be considered as the L5 segment based on the number of the fluorescent signals (above 20). L5 spinal segment could be differentiated from L4 and L6 segment based on their morphological characteristics under Cresyl violet stain. In L5-Tx group, at 2 and 4 weeks post-transection, the number of L5 spinal motoneurons was reduced by 8%. Meanwhile, Sc-Tx and Su groups showed no statistically notable changes. In this study, the authors could propose more reliable peripheral nerve axotomy model than the conventional sciatic nerve axotomy model by specifically transecting L5 spinal nerve and confining the investigating area within the L5 spinal segment.

Comparative Study of the L5 Spinal Nerve Transection Model and Sciatic Nerve Axotomy Model as a Peripheral Nerve Injury Model in Rat / 체질인류학회지

The aim of this study was to propose new more reliable peripheral nerve transection model to overcome the defect of the traditional sciatic axotomy model by specifically transecting L5 spinal nerve just after emerging from the intervertebral foramen and confining analysis area to the L5 spinal segment. The adult male Sprague-Dawley rats, weighing 300~350 g at the time of surgery, were used for the experiments. Four different experimental groups were used. 1. Sciatic nerve transection (Sc-Tx) group: transect the sciatic nerve in the popliteal fossa where it divided into the common peroneal nerve and tibial nerve. 2. L5 spinal nerve transection (L5-Tx) group: L5 spinal nerve was specifically transected. 3. Suture (Su) group: L5 spinal nerve was transected and immediately sutured. 4. Control group: the same surgical procedure with L5 spinal nerve transection group was performed except for the excision of L5 spinal nerve. To distinguish L5 motoneurons from the other level ones, the animals were received the retrograde tracer, FluoroGold into the axotomized proximal nerve stump. Serial coronal frozen sections at 40 microm thick through the L4 to L6 spinal segment was performed and the resultant total number of sections was about 180. Approximate serial 50 sections (approximately 2 mm) could be considered as the L5 segment based on the number of the fluorescent signals (above 20). L5 spinal segment could be differentiated from L4 and L6 segment based on their morphological characteristics under Cresyl violet stain. In L5-Tx group, at 2 and 4 weeks post-transection, the number of L5 spinal motoneurons was reduced by 8%. Meanwhile, Sc-Tx and Su groups showed no statistically notable changes. In this study, the authors could propose more reliable peripheral nerve axotomy model than the conventional sciatic nerve axotomy model by specifically transecting L5 spinal nerve and confining the investigating area within the L5 spinal segment.

c-Fos Immunoreactivity in the Neurons of the Lateral Geniculate Nucleus in Albino Rats by Light Exposure after Dark Rearing

PURPOSE: To investigate the effect of dark rearing immediately after birth on the maturation of the visual relay neurons in the lateral geniculate nucleus. METHODS: Fifty neonatal rats were used. Neonates of the control groups were raised under a normal light/dark cycle. Neonates of the experiment groups were dark reared and isolated from light during the entire experimental period, then exposed to the sun light for 1 hour before sacrifice. RESULTS: In the control groups, the neurons in the dorsal lateral geniculate nucleus developed normally at each age tested. In the experiment groups, the cytoplasm of the large neurons in the dorsal lateral geniculate nucleus of 2-week-old rats contained small vesicles, and the cytoplasm of the large neurons of 4-week-old rats was converted into a vacuole-like space. Moreover, c-Fos immunoreactivity of the large neurons in the dorsal lateral geniculate nucleus in the experiment groups was significantly increased compared to that of the control groups. CONCLUSIONS: We suppose that the maturation of the neurons in the lateral geniculate nucleus might be influenced by light stimulation during the critical period. Furthermore, c-Fos could be a marker of the functional activity of the visual relay neurons of the lateral geniculate nucleus in albino rats.

Expression of ErbB4 in the neurons of Alzheimer's disease brain and APP/PS1 mice, a model of Alzheimer's disease / 대한해부학회지

Neuregulin-1 (NRG1) plays important roles in the development and plasticity of the brain, and has also been reported to exhibit potent neuroprotective properties. Although ErbB4, a key NRG1 receptor, is expressed in multiple regions in the adult animal brain, little is known about its role in Alzheimer's disease (AD). AD is characterized by progressive impairment of cognition and behavioral disturbance that strongly correlate with degeneration and death of neurons in the cerebral cortex and limbic brain areas, such as the hippocampus and the amygdala. Here, we show that the ErbB4 and phospho-ErbB4 immunoreactivities were higher intensity in the neurons of the CA1-2 transitional field of AD brains as compared to age-matched controls. Also, ErbB4 expression was increased in the neurons of the cortico medial nucleus amygdala, human basal forebrain and superior frontal gyrus of AD brains. In cerebral cortex and hippocampus of amyloid precursor protein/presenilin 1 double transgenic mice, ErbB4 immunoreactivity significantly increased in comparison to age-matched wild type control. These results suggest that up-regulating of ErbB4 immunoreactivity may involve in the progression of pathology of AD.

Expression of ErbB4 in the apoptotic neurons of Alzheimer's disease brain / 대한해부학회지

Neuregulin-1 (NRG1) signaling participates in the synaptic plasticity, maintenance or regulation of adult brain. Although ErbB4, a key NRG1 receptor, is expressed in multiple regions in the adult animal brain, little is known about its localization in Alzheimer's disease (AD) brains. We previously reported that ErbB4 immunoreactivity showed regional difference in the hippocampus of age-matched control. In the present paper, immunohistochemical characterization of the distribution of ErbB4 receptor in the hippocampus relative to pathology staging were performed in age-matched control (Braak stage 0, n=6) and AD (Braak stage I/V, n=10). Here, we found that ErbB4 immunoreactivity was significantly increased in apoptotic hippocampal pyramidal neurons in the brains of AD patients, compared to those of age-matched control subjects. In AD brains, ErbB4 immunoreactivity was demonstrated to colocalize with the apoptotic signal Bax in apoptotic hippocampal pyramidal neurons. These results suggest that up-regulation of ErbB4 immunoreactivity in apoptotic neuron may involve in the progression of pathology of AD.

Development of Human Neuro-digital Slides and Neuro-atlas for Neuroscience Tutorial I (Spinal Cord and Brain Stem) / 체질인류학회지

In order to present the optimal neuroscience tutorial material for medical students and researchers, this study is aimed to make neuro-digital slide and neuro-atlas based on the histological specimens of human spinal cord and brain stem. Cadavers which had agreed for organ donation for research purpose were used in this study. Brains and spinal cords were extracted within 24 hours after death, and then fixed with 10% neutral buffered formalin. Paraffin blocks were made with the following regions; 8 regions from the spinal cord (the levels of the upper cervical segment, the cervical enlargement, the upper thoracic segment, the mid thoracic segment, the lower thoracic segment, the upper lumbar segment, the lumbar enlargement, the sacral segment), 14 regions from the brain stem (the levels of the spinomedullary junction, the pyramidal decussation, the medial lemniscus decussation, the obex, the mid-olivary medulla, the upper medulla, the pontomedullary junction, the lower pons, the mid pons, the upper pons, the isthmus rhombencephali, the inferior colliculus, the superior colliculus, the posterior commissure). Using virtual microscope software, we made digital neuro-slides which can be used anywhere and anytime regardless of equipment of microscope. To help understanding anatomy and functions of nervous tissue, we also made neuro-atlas based on the digital slide images. As results, the outline and detailed structures of nuclei and tracts are easily discriminated and also matched with marks and nomenclatures of neuro-atlas. Moreover, the cytoarchitecture of each nucleus and histological features can be well distinguished. We hope that this product would be used as a useful neuroscience tutorial material for the medical and paramedical school students, clinical trainees like interns and residents, and also neuroscience researchers.

Case Report of the Bilateral Absence of the Musculocutaneous Nerve Combined with the Unilateral Brachioradial Artery / 체질인류학회지

During the routine gross anatomical dissection, bilateral absence of the musculocutaneous nerve and unilateral brachioradial artery were found in a 76-year-old Korean male cadaver. At the apex of the axilla, the lateral cord of the brachial plexus united into the median nerve without branching off the musculocutaneous nerve. The flexor arm musculatures, normally innervated by the musculocutaneous nerve, were innervated by two separate branches from the median nerve. The distal one continued as the lateral antebrachial cutaneous nerve. In addition, the radial artery of the left arm was originated from the middle one-third of the brachial artery. At bifurcation, it lay deep to the median nerve and crossed it medially. However, at the elbow, it crossed again the median nerve anterolaterally. Just above the cubital fossa, it anastomosed with the brachial artery. The arterial distribution of the right arm was normal. The separate reports which described the absence of the musculocutaneous nerve or brachioradial artery have been reported. However, this combined variation has not been documented until now.

Neuroprotective Effect of Diazoxide in Animal Model of Focal Cerebral Ischemia / 대한해부학회지

Ischemic preconditioning is the earlier stress adaptive response that occurs during repeated episodes of the brief ischemia and reperfusion. It is now well known that this adaptive response can render the neuron more tolerant to the subsequent potential lethal ischemic injury. Although the selective mitochondrial K+ (ATP) channel opener induces protective effects similar to that of ischemic preconditioning, the underlying mechanism is not known yet. The purpose of this study was to investigate the mechanism of neuroprotective effect of diazoxide, a mitochondrial K+ (ATP) channel opener, pretreatment on a focal cerebral ischemic injury of rat brain. Thirthy-four Sprague-Dawley rats were used. Animals were randomly divided into normal control group, middle cerebral artery (MCA) permanent occulusion group (experimental control group), and diazoxide pretreated group. Animals were sacrified at 2 hours or 24 hours after MCA occulusion injury. For inducing the focal cerebral ischemic injury, the left MCA was occuluded by modified Longa's method. Diazoxide (3 mg/kg) was administrated through the femoral artery at 15 minutes earlier to surgical procedures. TTC-stained brain sections of experimental group showed a remarkable infarct injury in the ipsilateral cerebral cortex and striatum. However, the infarction volume of the diazoxide pretreated group was significantly reduced. Accordingly, the number of neurons undergoing eosinophilic degeneration and nuclear chromatin condensation was reduced by diazoxide pretreatment. TUNEL-positive neurons were not detected at 2 hours after MCA permanent occlusion but lots of them were observed at 24 hours. The number of c-fos immunoreactive neurons was remarkably increased at 2 hours following MCA permanent occulusion and reduced to the basal level at 24 hours in both experimental control and diazoxide pretreated group. However, the number of Bcl-2 or pAkt immunoreactivitive neurons of the diazoxide pretreated group outnumbered those of the experimental control group at all timepoints in our experiment. In conclusion, the pretreatment of diazoxide, K+ channel opener, could have europrotective effects on ischemic neurons by upregulating the expression of anti-apoptotic proteins, like Bcl-2 or pAkt.

An Immunohistochemical Study of ErbB4 Receptor in Alzheimer's Disease Hippocampus / 대한해부학회지

Neuregulin-1 (NRG1) signaling participates in numerous neurodevelopmental processes. Although ErbB4, a key NRG1 receptor, is expressed in multiple regions in the adult animal brain, little is known about its expression in aged human brain. We show that ErbB4 immunoreactivity was shown regional difference in the hippocampus of age-matched control and that the distribution of these molecules was altered in Alzheimer's disease (AD) brains. Immunohistochemical characterization of the distribution of ErbB4 receptor in the hippocampus relative to pathology staging were performed in age-matched control (Braak stage I/II, n=5), early AD (Braak stage III/IV, n=5) and advanced AD(Braak stage V/VI, n=10). The intensity of ErbB4 immunoreactivity was higher in neurons of the CA2 than that in CA1 or CA3 in the age-matched control. Particularly, in the early AD, ErbB4 immunoreactivity was significantly increased in the apoptotic cells of the CA2 field. In the advanced AD, ErbB4 immunostaining was more intense in the apoptotic cell of the CA2 field. In the dentate gyrus (DG), ErbB4-positive granular cell density was gradually increased in proportion to the progression of pathology of AD brains. We have also found that ErbB4 immunostaining was increased in the nucleus, suggesting that the presenilin-dependent cleavage of ErbB4 generates the soluble ErbB4 ICD (intracellular domain) that translocalized to the nucleus. Together, these results provide the immunohistochemical analysis of ErbB4 receptor in the human hippocampus staged by the progression of pathology of AD.

Expression of Activating Transcription Factor 3 in Ischemic Penumbra Region Following Focal Cerebral Ischemia / 대한해부학회지

It has been demonstrated that some of immediate early genes (IEGs) such as c-Jun or fos are induced immediately following neuronal injury and they play an important role in determining the fate of the injured neurons. Of IEGs, the activating transcription factor 3 (ATF3) is focused by many investigators, because they are expressed in various types of neural insults and have been known to serve a diverse function in both neuronal survival and death. However, little is known about the functional role of ATF3 in ischemic brain injury. So in this study, the authors examined the expression pattern of the activating transcription factor 3 (ATF3) following middle cerebral artery (MCA) occlusion-reperfusion injury. According to the findings obtained by triphenyltetrazolium chloride (TTC) stains, the authors have classified the infarcted area into two regions, the ischemic core region and the ischemic penumbra region. In both regions, many neurons underwent neuronal degeneration, characterized by the shrunken nuclei with eosinophilic perikaryon. The H & E stain also demonstrated the increased number of probable activated astrocytes and microglia in the ischemic brain regions and this was confirmed by GFAP- and OX42-immunohistochemistry. Immunohistochemical study for ATF3 also demonstrated the specific upregulation of ATF3 in the nuclei of neurons under ischemic injury, but not in those of the contralateral regions. Interestingly, the number of the ATF3 positive neurons in the ischemic penumbra regions outnumbered that of the ischemic core regions. Based on many reports that the neuronal death in ischemic penumbra region is caused by programed cell death rather than by necrosis which is main cause of neuronal death in ischemic core region, our results could suggest that the ATF3 is an important IEGs which determine the fate of the ischemic neurons.

Modulation of Alveolar Surfactant after Lower Cervical Vagotomy / 대한해부학회지

Pulmonary surfactant prevents alveolar collapse by reducing alveolar surface tension and aids gaseous exchange in the lung. Since inadequate production of pulmonary surfactant is a key etiological process in ARDS, surfactant may play an important role in pathogenesis of ARDS. To provide a clue for establishing pathological mechanism of post-traumatic or neurogenic ARDS, we studied the influence of the vagal innervation on pulmonary surfactant metabolism. A total of 20 S-D rats (about 230 gm wt. each) were divided into two conditions: normal control and vagotomized groups. The vagotomized rats were subdivided into 3 hours, 8 hours and 24 hours groups. To preserve the superior cervical cardiac branches, both vagus nerves were cut at the lowest part of the carotid triangle. Cannula for adequate respiration and suction was fitted into the trachea. The lung tissue were processed for H&E, Masson's trichrome, Immunohistochemistry using anti-surfactant protein A (SP-A) and .anti-prosurfactant protein C (ProSP-C). The results were as follows; 1. The lungs of the vagotomized rats showed alveolar edema, fibrosis with infiltration of inflammatory cells and hyaline membrane formation. 2. In the lungs of the vagotomized rats, SP-A and ProSP-C immunoreactivity was decreased in proportion to postoperation time. Consequently, it can be postulated that autonomic disturbances caused by vagal interruption may induce ARDS-like pulmonary damage by modulating alveolar surfactant protein metabolism and by evoking the secondary inflammatory processes.

Immunohistochemical Study on GTP-binding Rab6 Expression in the Hippocampal Cortices of the Alzheimer Brain / 대한해부학회지

The ras-related GTP binding protein, rab6, is located in late Golgi compartment. Modulation of beta-and gamma-secretase activity may lead to production of beta-amyloid fragments that are ultimately deposited in senile plaques at the brain of Alzheimer patients. Because modulation of rab6-mediated intracellular transport has been known to affect amyloid precursor protein (APP) processing, we investigated the rab6 immunoreactivity on the hippocampal neurons in the Alzheimer brains, according to the pathological staging of the disease. A total of 30 brains were used for this study. Campbell's silver stain for beta-amyloid and immunohistochemistry for rab6 protein were employed. The cortices of the hippocampal formation and the neighboring temporal neocortex were observed. The results are obtained as follows: 1. In normal elderly brains, no amyloid plaque is seen. In Alzheimer brains, a number of amyloid plaques are seen at the temporal neocortex and dentate gyrus. 2. In normal elderly brains, the perikaria of the pyramidal cells at the CA1 sector shows weak rab6 immunoreactivity. At the CA2 and CA3 sectors, trace immunoreactivity is observed in the pyramidal cells. 3. In preclinical Alzheimer brains, the perikaria of the pyramidal cells at the CA1 sector shows moderate rab6 immunoreactivity and the cells at the CA2 sector show weak immunoreactivity. A weak to moderate imunoreactivity is seen in the pyramidal cells of the CA3 sector. 4. In clinical Alzheimer brains, the pyramidal cells at the CA1 and CA3 sectors show strong rab6 immunoreactivity, but the cells at the CA2 sector shows moderate immunoreactivity. It is suggested that alteration of intracellular protein transport caused by abnormal rab6 activity may modulate amyloid precursor protein processing, which results in beta-amyloid production.

Localization of Laminin and Laminin beta 1 chain on Gomeruli of Developmental Rat Kidney / 체질인류학회지

Laminin, an extracellular matrix glycoprotein composed of three polypeptide chains such as alpha , beta, and gamma is distributed in basement membranes of epithelium, muscle, and nervous tissues. Laminin functions as an extracellular cytoskeleton and regulates the differentiation and polarization of cells adjacent to the basement membrane. Along with type IV collagen and heparan sulfate proteoglycan, laminin forms a spike -like structure in the renal glomerular basement membrane (GBM). It has been previously demonstrated that the distribution and immune reaction of laminin are changed in response to the conditions of glomerulonephritis and that laminin plays a role in the reformation of GBM as well as the regeneration of renal glomerular cells. In the present study, the profile of expression and distribution of laminin/laminin beta1 chain were examined in different developmental stages and upon adriamycin administration. Kidney obtained from fetuses (16, 18, and 20 days old) and infants (1 and 7 days old) of Sprague -Dawley rats were either cryosectioned for immunohistochemical assays or ultrathin -sectioned for electron microscopy using immunogold staining methods. The results were as follows: 1. Intensive expression of laminin was observed in the GBM and surrounding mesenchymal tissues obtained from 16, 18, and 20 days old fetuses and in the glomerulus from one day neonates, whereas the level of staining decreased in the glomerulus from 7 days old infants. 2. Immunogold particles were observed in the comma -shaped nephron, in particular in cisternae of rough endoplasmic reticulum, vesicles and nuclear membrane of endothelial cells and mesangial cells obtained from 18 days old fetuses. 3. The immune reactions of laminin beta1 chain were trace detected in the kidney from fetuses (16, 18, and 20 days old) and weakly in tissues surrounding blood capillary and mesangial tissues from one day old neonates. 4. After 24 hours following adriamycin treatment, the reactivity of laminin was slightly enhanced in the renal glomerulus, when compared with that of untreated controls. This enhancement persisted up to 1 week of adriamycin treatment. Laminin beta1 chain was weakly detectable, while further treatment with adriamycin for another 24 hours reduced the intensity of laminin beta1 chain. Taken together, these results suggest that laminin is localized in the GBM at the high level during early fetal stages but the expression levels decrease after birth. Moreover, administration with adriamycin may result in an increase in the immune reactivities of laminin and laminin beta1 chain by renal tissue damage followed by renal regeneration.

Protective Roles of Adenosine A1 Receptor Agonist and KATP Channel Opener in Adriamycin induced Cardiac Toxicity / 체질인류학회지

Although adriamycin is a potent chemotherapeutic agent, it elicits serious adverse effects, including cardiac toxicity. Evidence suggests that congestive heart failure induced by adriamycin is mediated by oxidative stress. We investigated whether regulators of adenosine A1 receptor and KATP channel, which have been demonstrated to mediate protective effects of ischemic -preconditioning in myocardium, are able to modulate adriamicin -induced impairment of cardiomyocyte. To study the effect of antioxidant, adenosine A1 receptor agonist & antagonist and KATP channel agonist & antagonist, ICR mice were pretreated with Cu,Zn -SOD, dimethyl thiourea, RPIA (R (-)N6 -(2 -Phenylisopropropyl)- adenosine, adenosine A1 receptor agonist), 8 -CPDPX (8 -Cyclopentyl -1, 3 -dipropylxanthine, adenosine A1 receptor antagonist), Pinacidil (KATP channel opener) and glibenclamide (KATP channel closer), followed by i.p injection with adriamycin. Mice were sacrificed day 1 or day 4 after adriamycin injection and cardiac toxicity was accessed by measurement of creatine phosphokinase (CK) levels in serum, immunohistochemistry using anti -Bcl -2 antibody and TUNEL histochemical assay. As expected, pretreatment of mice with Cu, Zn -SOD and DMTU reduced the frequency of TUNEL positive cells, indicating antioxidants protected cardiocytes from adriamycin -induced apoptosis. Interestingly, pretreatment with RPIA and pinacidil induced a significant decrease in adriamycin -induced cytotoxicity, whereas 8 -CPDPX and glibenclamide generated the opposite results. In Bcl -2 immunohistochemistry, an increased expression of Bcl -2 was found in all ADR treated groups, especially in glibenclamide pretreated group, and 8 -CPDPX pretreated groups, but Bcl -2 failed to protect myocytes from apoptosis. All ADR treated groups exhibited elevated levels of serum CK, compared with nomal controls, especially mice sacrificed at day 4 than those at day 1, and showed similar patterns of TUNNEL assay, reflecting heart tissue damages. This observation implicated cytoprotective roles of RPIA and pinacidil against adriamycin -induced cardiac toxicity. In conclusion, these results demonstrated that adriamycin -induced cardiotoxicity was associated with the generation of reactive oxygen species and that regulators including SOD, DMTU, RPIA and pinacidil elicited protective effects on this toxicity. In particular, pinacidil, the KATP channel opener, was more effective than RPIA, the adenosine A, receptor agonist, to attenate the adriamycin -induced cardiac toxicity.

Effect of Thiamine Deficiency on the Glial Fibrillary Acidic Protein ( GFAP ) Immunoreacitivity of the Astrogial Cells in Rat Forebrain

BACKGROUND: Diverse injury to central nervous system results in proliferation and hypertrophy of astrocytes. The hallmark of this response is enhanced expression of the major intermediate filament protein of astrocyte, glial fibrillary acidic protein(GFAP). These obsevations suggested that GFAP may be a useful biochemical indicator of neurotoxicity. This study is designed for investigating the chronological effects of the thiamine deficiency on the astrogrial GFAP immunoreactivity in the rat forebrain, and for comparing the difference between time-sequenital morphological changes of luxol fast blue-cresyl violet stain reported in previous study and GFAP immunoreactivity. METHODS: A total of 40 healthy Sprague-Dawley strain rats, weighing about 200gm were used as experimental animals(10 control, 30 thiamine deficient rats). Pyrithiamine was injected intraperitonially for 9 days and thiamine deficient diet was continuously supplied until sacrifice. Thiamine deficient rats were subdivided into 3 groups according to thiamine deficient state. Immunohistochemical stains for GFAP in the regions of thalamus, medial mammillary nucleus and CA1 sector in hippocampus were performed by free floating method in cell culture plate. All preperations were observed with light microscope. RESULTS: GFAP immunoactivities at thalamus were tracely positive(+) in controls, strongly positive(+++) in group I, and moderately positive(++) in group II and III. But GFAP immunoactivities at medial mammillary nucleus were tracely positive( ) in controls, moderately positive(++) in group I and III , and strongly positive(+++) in group II. At the CA1 region of hippocampus, the immunoactivities were weakly positive in controls , strongly positive(+++) in group I and II, and moderately positive(++) in group III. The diverse patterns of GFAP immunoreactivities in each vulnerable site were different from the previous morphological study. In luxol-fast and cresyl violet staining, the neuronal damage and necrosis were marked in group III, group II, and group I, in that order, which findings are consistent in all regions. CONCLUSIONS: Different patterns of time-sequential GFAP immunoactivities at each vulnerable site suggest that there are regional differences in sensitivity and resistance to thiamine deficiency.

Morphologic Studies on Forebrain of Thiamine Deficient Rats Induced by Thiamine eficient Diet and Pyrithiamine

OBJECTIVE: This study was designed for developing a new experimental animal model of Wernicke's encephalopathy, and for investigating the timesequential morphological changes in the thiamine deficient rat brain by thiamine deficient diet with short term treatment of pyrithiamine. METHODS: A total of 40 healthy Sprague-Dawley strain rats, weighing about 2OOgm were used as experimental animals, divided into 10 control rats and 30 thiamine deficient experimental rats. Pyrithiamine (50mg/lOOgm/day) was injected intraperitonially for 9 days and thiamine deficient diet (20gm/rat/day) was continuously supplied until sacrifice. Then thiamine deficient experimental rats were subdivided into 3 groups according'to the exposure time of thiamine deficiency. For observing the morphological features in thalamus, medial mammillary nucleus and CA, sector in hippocampus, luxol-fast blue-cresy violet stain was performed. RESULTS: Treatment with pyrithiamine and thiamine deficient diet results in weight loss and decrement of body temperature on the 12th-14th day, followed by various neurologic manifestations, such as ataxia, hypotonia, circling movement, opisthotonus and loss of righting reflex, on the 16th-20th day, and then died on the 23th-25th, day. Chromatolysis and nuclear condensation of neurons in thalamus, medial mammillary nucleus and CA1 region of hippocampus are observed in group I. Mild edematous changes with neuronal necrosis in group II, and marked neuronal loss with severe edematous necrosis in group III are noted in same regions. CONCLUSION: These time sequential consistent morphological changes suggest that our experimental method could be used as a new animal model of Wernicke's encephalopathy in studying the sequential changes of thiamine deficient rat brain.