Effect of calcium silicate-based sealer to bone tissue of mandible of rats

Purpose@#To histologically evaluate the effects of three calcium silicate-based sealers on rat mandible tissue. @*Materials and Methods@#Rats were randomly divided as follows: A group that sacrificed immediately after cavity preparation, a group that sacri-ficed two weeks after cavity preparation, a group that sacrificed two weeks after CeraSeal (CS), AH Plus Bioceramic (AHB), or OneFil (OF) sealer injection, respectively. After tissue processing for all groups, the bone tissue area (%) and the number of osteoclasts in and around the cavity were measured under a microscope. The results of each group were compared and statistical analysis was performed using one-way ANOVA and Tukey’s test. @*Results@#The formation of bone tissue and the presence of osteoclasts in the cav-ity were observed in the group that sacrificed two weeks after cavity preparation and the group sacrificed two weeks after AHB seal-er injection, and these groups showed significantly higher average bone tissue area (%) than the other groups. In the other groups, no inflammation or foreign body reaction occurred in the cavity, and no osteoclasts were observed. @*Conclusion@#All calcium silicatebased sealers used in this study showed a favorable bone tissue response when injected into the rat mandible. In particular, higher bone formation in the cavity was observed in AHB.

Application time and persistence of transcranial direct current stimulation (tDCS) against neuronal death resulting from transient cerebral ischemia / 한국실험동물학회지

Background@#Transcranial direct current stimulation (tDCS) has been studied as a tool to stimulate the functional recovery of neurons after stroke. Although this device has recently begun to be utilized for providing neuroprotection in stroke, research on its application conditions is lacking. This study aimed to examine the effects of various tDCS application conditions on cerebral ischemia. Ischemia was induced for 5 min in a gerbil model. The application of tDCS comprised a 20 min stimulation—20 min rest—20 min stimulation protocol, which was implemented simultaneously with the induction of cerebral ischemia. Application time of the tDCS effect on ischemia was confirmed by sampling brain tissues after stimulation using 0.2 mA tDCS at 0, 5, 10 and 60 min after ischemia. @*Results@#Persistence of the tDCS effect on ischemia was confirmed by sampling brain tissues 5, 7, and 10 days post stimulation, with 0.2 mA tDCS after ischemia. Furthermore, the tissues were stained with cresyl violet and Fluoro-Jade C so as to determine the reduction in neuronal death under all application conditions. @*Conclusions@#The application of tDCS can be used as a useful intervention for acute phase stroke due to its sustained neuroprotective effect.

Flavonoids as anti-inflammatory and neuroprotective agents

Neuroinflammation is known as the main mechanism implicated in the advancement of neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. The main feature of neuroinflammation is associated with the activation of microglia. The activated microglia increase proinflammatory cytokine production and induce progressive neuronal cell death. Citrus flavonoids show neuroprotective effects that are associated with the anti-inflammatory action of flavonoids in neurodegenerative diseases. Among these citrus flavonoids, kaempferol, naringin, and nobiletin show inhibitory effects on nuclear factor-κB and mitogen-activated protein kinase signaling pathways that can modulate inflammatory conditions in microglial cells. In the present review, we present the anti-inflammatory activities of citrus flavonoids and therapeutic potential of flavonoids as neuroprotective agents.

Extract Promotes Neurogenesis in the Hippocampal Dentate Gyrus of the Adult Mouse through Increasing Expressions of Brain-Derived Neurotrophic Factor and Tropomyosin-Related Kinase B / 中华医学杂志(英文版)

<p><b>Background</b>Glehnia littoralis has been used for traditional Asian medicine, which has diverse therapeutic activities. However, studies regarding neurogenic effects of G. littoralis have not yet been considered. Therefore, in this study, we examined effects of G. littoralis extract on cell proliferation, neuroblast differentiation, and the maturation of newborn neurons in the hippocampus of adult mice.</p><p><b>Methods</b>A total of 39 male ICR mice (12 weeks old) were randomly assigned to vehicle-treated and 100 and 200 mg/kg G. littoralis extract-treated groups (n = 13 in each group). Vehicle and G. littoralis extract were orally administrated for 28 days. To examine neurogenic effects of G. littoralis extract, we performed immunohistochemistry for 5-bromo-2-deoxyuridine (BrdU, an indicator for cell proliferation) and doublecortin (DCX, an immature neuronal marker) and double immunofluorescence staining for BrdU and neuronal nuclear antigen (NeuN, a mature neuronal marker). In addition, we examined expressional changes of brain-derived neurotrophic factor (BDNF) and its major receptor tropomyosin-related kinase B (TrkB) using Western blotting analysis.</p><p><b>Results</b>Treatment with 200 mg/kg, not 100 mg/kg, significantly increased number of BrdU-immunoreactive () and DCX cells (48.0 ± 3.1 and 72.0 ± 3.8 cells/section, respectively) in the subgranular zone (SGZ) of the dentate gyrus (DG) and BrdU/NeuN cells (17.0 ± 1.5 cells/section) in the granule cell layer as well as in the SGZ. In addition, protein levels of BDNF and TrkB (about 232% and 244% of the vehicle-treated group, respectively) were significantly increased in the DG of the mice treated with 200 mg/kg of G. littoralis extract.</p><p><b>Conclusion</b>G. littoralis extract promots cell proliferation, neuroblast differentiation, and neuronal maturation in the hippocampal DG, and neurogenic effects might be closely related to increases of BDNF and TrkB proteins by G. littoralis extract treatment.</p>

Determination of the optimal diabetes duration for bone regeneration experiments in an alloxan-induced diabetic rabbit calvarial defect model

PURPOSE: The purpose of this study was to evaluate the optimal diabetes duration for bone regeneration experiments in an alloxan monohydrate (ALX)–induced diabetic rabbit calvarial defect model by evaluating the association between diabetes duration and bone healing capacity. METHODS: Twenty-four New Zealand white rabbits were used. Twenty-two rabbits were injected with 100 mg/kg of ALX to induce experimental diabetes. These rabbits were divided into 4 groups, including a control group and groups with diabetes durations of 1 week (group 1), 2 weeks (group 2), and 4 weeks (group 3). Calvarial defects were created at 1, 2, and 4 weeks after ALX injection and in the control rabbits. Cone-beam computed tomography (CBCT) scanning was performed on the day of surgery and at 2 and 4 weeks after surgery. The rabbits were sacrificed 4 weeks after surgery, followed by histological and immunofluorescence analysis. RESULTS: The diabetic state of all diabetic rabbits was well-maintained throughout the experiment. Reconstructed 3-dimensional CBCT imaging showed more rapid and prominent bone regeneration in the control group than in the experimental groups. Histological staining showed notable bone regeneration in the control group, in contrast to scarce bone formation in the experimental groups. The appearance and immunoreactivity of receptor activator of nuclear factor-kappa B and osteoprotegerin did not show notable differences among the groups. CONCLUSION: ALX administration at 100 mg/kg successfully induced experimental diabetes in rabbits. The effect of diabetes on bone healing was evident when the interval between diabetes induction and the intervention was ≥1 week.

Study on the Changes in Distributions and Expressions of Aquaporin5 (AQP5) in Salivary Glands of Mice After Alcohol Ingestion

Alcohol intake is known to affect various organs in the human body, causing reduction of salivation in the oral cavity. Hypo-salivation effect of alcohol is a common feature, but the mechanism in salivary glands is still poorly studied. Therefore, in this study, the changes in salivary secretion and water channel protein (aquaporin5, AQP5) in salivary glands of mice were investigated after ethanol administration. Animals were divided in to 4 groups with the control, 4 g/kg ethanol, 8 g/kg ethanol and 16 g/kg ethanol administration groups. One hour after ethanol administration, saliva was collected from the oral cavity, and the animals were killed and parotid and submandibular glands were extracted to analyze the histopathology, AQP5 immunihistochemistry and AQP5 protein level. According to the results, the salivation rate decreased irrespective of the ethanol dose in mice, and viscosities increased with increase in ethanol dose. However, there were no pathological changes in parotid and submandibular glands due to ethanol administration. Expression of AQP5 in parotid and submandibular glands decreased with increase ethanol administration These results indicate that the reduction of salivary secretion due to acute alcohol intake is closely related to decrease of the water channel protein such as AQP5 in parotid glands and submandibular glands, rather than the damage of salivary glands.

Determination of the critical diabetes duration in a streptozotocin-induced diabetic rat calvarial defect model for experimentation regarding bone regeneration

PURPOSE: The purpose of this study was to determine the critical diabetes duration in a streptozotocin (STZ)-induced diabetic rat calvarial defect model for experimentation regarding bone regeneration by evaluating the association between diabetes duration and bone healing capacity through histological and radiographic analyses. METHODS: Experimental diabetes was induced in 50 of 60 rats by an STZ injection. The rats were divided into 5 groups, including a control group (group 1), according to diabetes durations of 0, 2, 4, 6, and 8 weeks, respectively. Eighteen rats survived: 4 in group 1, 4 in group 2, 4 in group 3, 5 in group 4, and 1 in group 5. Calvarial defects were created at 0, 2, 4, 6, and 8 weeks after STZ injection in groups 1–5. Cone-beam computed tomography scanning was performed at baseline and at 5 and 7 weeks after surgery. The rats were sacrificed 7 weeks after surgery, followed by histological evaluation. RESULTS: The voxel gray values (VGVs) of group 1 and group 2 increased, whereas the VGVs of group 3 and group 4 decreased starting 5 weeks after surgery, although this trend did not reach statistical significance between groups. On the reconstructed 3-dimensional images and based on an analysis of histological features, groups 1 and 2 showed apparent bone regeneration, while groups 3–5 showed very limited bone regeneration. CONCLUSIONS: The critical diabetes duration in an STZ-induced diabetic rat calvarial defect model for experimentation regarding bone regeneration was between 2 and 4 weeks. It is suggested that researchers who use STZ-induced diabetic rats wait for more than 2 weeks following diabetes induction before placing implants or conducting bone regeneration studies to allow definite disturbances in bone healing to emerge.

Study on Changes in Endogenous Stem Cells in the Salivary Gland of Streptozotocin-induced Diabetic Rats

Type1 diabetes mellitus (DM) is generally known to be caused by destruction of insulin-producing pancreatic β cells or an immune-related problem. Polydipsia is a representative symptom of DM, and it has been reported that this condition is closely related to xerostomia and is considered that hyposalivation from the salivary gland results in this phenomenon. Although various studies have reported that induction of diabetes reduces endogenous stem cells in other organs (heart, brain etc.), diabetes-related changes in endogenous stem cells in the salivary gland have not yet been well established. Therefore, in this study, to verify the change in salivary gland stem cells after diabetes, salivary gland tissues in the control and diabetes-induced groups were processed by histochemistry (Masson's trichrome staining) for morphological analysis, TUNEL assay for cell death, and immunohistochemistry (Ki-67 and c-Kit) for cell proliferation and maturation. Diabetes induced by STZ leads to vacuolization, apoptosis, and reduction in proliferating cells/salivary gland stem cells in salivary glands of rats. This result suggests that diabetes may be associated with reduction in salivary gland function such as degeneration and inhibition of regeneration in the salivary gland.

Oenanthe Javanica Extract Protects Against Experimentally Induced Ischemic Neuronal Damage via its Antioxidant Effects / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Water dropwort (Oenanthe javanica) as a popular traditional medicine in Asia shows various biological properties including antioxidant activity. In this study, we firstly examined the neuroprotective effect of Oenanthe javanica extract (OJE) in the hippocampal cornus ammonis 1 region (CA1 region) of the gerbil subjected to transient cerebral ischemia.</p><p><b>METHODS</b>Gerbils were established by the occlusion of common carotid arteries for 5 min. The neuroprotective effect of OJE was estimated by cresyl violet staining. In addition, 4 antioxidants (copper, zinc superoxide dismutase [SOD], manganese SOD, catalase, and glutathione peroxidase) immunoreactivities were investigated by immunohistochemistry.</p><p><b>RESULTS</b>Pyramidal neurons in the CA1 region showed neuronal death at 5 days postischemia; at this point in time, all antioxidants immunoreactivities disappeared in CA1 pyramidal neurons and showed in many nonpyramidal cells. Treatment with 200 mg/kg, not 100 mg/kg, OJE protected CA1 pyramidal neurons from ischemic damage. In addition, 200 mg/kg OJE treatment increased or maintained antioxidants immunoreactivities. Especially, among the antioxidants, glutathione peroxidase immunoreactivity was effectively increased in the CA1 pyramidal neurons of the OJE-treated sham-operated and ischemia-operated groups.</p><p><b>CONCLUSION</b>Our present results indicate that treatment with OJE can protect neurons from transient ischemic damage and that the neuroprotective effect may be closely associated with increased or maintained intracellular antioxidant enzymes by OJE.</p>

Powdered Wound Dressing Materials Made from wild Silkworm Antheraea pernyi Silk Fibroin on Full-skin Thickness Burn Wounds on Rats / 대한악안면성형재건외과학회지

PURPOSE: This study evaluated powdered burn wound dressing materials from wild silkworm fibroin in an animal model. METHODS: Fifteen rats were used in this experiment. Full-thickness 2x2 cm burn wounds were created on the back of rats under anesthesia. In the two experimental groups, the wounds were treated with two different dressing materials made from silkworm fibroin. In the Control Group, natural healing without any dressing material was set as control. The wound surface area was measured at five days, seven days and 14 days. Wound healing was evaluated by histologic analysis. RESULTS: By gross observation, there were no infections or severe inflammations through 14 days post-injury. The differences among groups were statistically significant at seven days and 14 days, postoperatively (P<0.037 and 0.001, respectively). By post hoc test, the defect size was significantly smaller in experimental Group 1 compared with the Control Group and experimental Group 2 at seven days postoperatively (P=0.022 and 0.029, respectively). The difference between Group 1 and Group 2 was statistically significant at 14 days postoperatively (P<0.001). Group 1 and control also differed significantly (P=0.002). Group 1 showed a smaller residual scar than the Control Group and Group 2 at 14 days post-injury. Histologic analysis showed more re-epithelization in Groups 1 and 2 than in the Control Groups. CONCLUSION: Burn wound healing was accelerated with silk fibroin spun by wild silkworm Antheraea pernyi. There was no atypical inflammation with silk dressing materials. In conclusion, silk dressing materials can be used for treatment of burn wound.

Comparison of arylalkylamine N-acetyltransferase and melatonin receptor type 1B immunoreactivity between young adult and aged canine spinal cord

Melatonin affects diverse physiological functions through its receptor and plays an important role in the central nervous system. In the present study, we compared immunoreactivity patterns of arylalkylamine N-acetyltransferase (AANAT), an enzyme essential for melatonin synthesis, and melatonin receptor type 1B (MT2) in the spinal cord of young adult (2~3 years) and aged (10~12 years) beagle dogs using immunohistochemistry and Western blotting. AANAT-specific immunoreactivity was observed in the nuclei of spinal neurons, and was significantly increased in aged dog spinal neurons compared to young adult spinal neurons. MT2-specific immunoreactivity was found in the cytoplasm of spinal neurons, and was predominantly increased in the margin of the neuron cytoplasm in aged spinal cord compared to that in the young adult dogs. These increased levels of AANAT and MT2 immunoreactivity in aged spinal cord might be a feature of normal aging and associated with a feedback mechanism that compensates for decreased production of melatonin during aging.

Neuroprotection via maintenance or increase of antioxidants and neurotrophic factors in ischemic gerbil hippocampus treated with tanshinone I / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Danshen (Radix Salvia miltiorrhizae) has been used as a traditional medicine in Asia for treatment of various microcirculatory disturbance related diseases. Tanshinones are mainly hydrophobic active components, which have been isolated from Danshen and show various biological functions. In this study, we observed the neuroprotective effect of tanshinone I (TsI) against ischemic damage in the gerbil hippocampal CA1 region (CA1) after transient cerebral ischemia and examined its neuroprotective mechanism.</p><p><b>METHODS</b>The gerbils were divided into vehicle-treated-sham-group, vehicle-treated-ischemia-group, TsI-treated-sham-group, and TsI-treated-ischemia-group. TsI was administrated intraperitoneally three times (once a day for three days) before ischemia-reperfusion. The neuroprotective effect of TsI was examined using H&E staining, neuronal nuclei (NeuN) immunohistochemistry and Fluoro-Jade B staining. To investigate the neuroprotective mechanism of TsI after ischemia-reperfusion, immunohistochemical (IHC) and Western blotting analyses for Cu, Zn-superoxide dismutase (SOD1), Mn-superoxide dismutase (SOD2), brain-derived neurotrophic factor (BDNF) and insulin-like growth factor-I (IGF-I) were performed.</p><p><b>RESULTS</b>Treatment with TsI protected pyramidal neurons from ischemia-induced neuronal death in the CA1 after ischemia-reperfusion. In addition, treatment with TsI maintained the levels of SOD1 and SOD2 as determined by IHC and Western blotting in the CA1 after ischemia-reperfusion compared with the vehicle-ischemia-group. In addition, treatment with TsI increased the levels of BDNF and IGF-I determined by IHC and Western blotting in the TsI-treated-sham-group compared with the vehicle-treated-sham-group, and their levels were maintained in the stratum pyramidale of the ischemic CA1 in the TsI-treated-ischemia-group.</p><p><b>CONCLUSION</b>Treatment with TsI protects pyramidal neurons of the CA1 from ischemic damage induced by transient cerebral ischemia via the maintenance of antioxidants and the increase of neurotrophic factors.</p>

Systemic administration of low dosage of tetanus toxin decreases cell proliferation and neuroblast differentiation in the mouse hippocampal dentate gyrus / 한국실험동물학회지

In the present study, we investigated the effect of Tetaus toxin (TeT) on cell proliferation and neuroblast differentiation using specific markers: 5-bromo-2-deoxyuridine (BrdU) as an exogenous marker for cell proliferation, Ki-67 as an endogenous marker for cell proliferation and doublecortin (DCX) as a marker for neuroblasts in the mouse hippocampal dentate gyrus (DG) after TeT treatment. Mice were intraperitoneally administered 2.5 and 10 ng/kg TeT and sacrificed 15 days after the treatment. In both the TeT-treated groups, no neuronal death occurred in any layers of the DG using neuronal nuclei (NeuN, a neuron nuclei maker) and Fluoro-Jade B (F-J B, a high-affinity fluorescent marker for the localization of neuronal degeneration). In addition, no significant change in glial activation in both the 2.5 and 10 ng/kg TeT-treated-groups was found by GFAP (a marker for astrocytes) and Iba-1 (a marker for microglia) immunohistochemistry. However, in the 2.5 ng/kg TeT-treated-group, the mean number of BrdU, Ki-67 and DCX immunoreactive cells, respectively, were apparently decreased compared to the control group, and the mean number of each in the 10 ng/kg TeT-treated-group was much more decreased. In addition, processes of DCX-immunoreactive cells, which projected into the molecular layer, were short compared to those in the control group. In brief, our present results show that low dosage (10 ng/kg) TeT treatment apparently decreased cell proliferation and neuroblast differentiation in the mouse hippocampal DG without distinct gliosis as well as any loss of adult neurons.

Detailed Differentiation of Calbindin D-28k-Immunoreactive Cells in the Dentate Gyrus in C57BL/6 Mice at Early Postnatal Stages / 한국실험동물학회지

The hippocampus makes new memories and is involved in mental cognition, and the hippocampal dentate gyrus (DG) is critical because neurogenesis, which occurs throughout life, occurs in the DG. We observed the differentiation of neuroblasts into mature neurons (granule cells) in the DG of C57BL/6 mice at various early postnatal (P) ages: P1, P7, P14, and P21 using doublecortin (DCX) immunohistochemistry (IHC) for neuroblasts and calbindin D-28k (CB) IHC for granule cells. DCX-positive cells decreased in the DG with age; however, CB+ cells increased over time. At P1, DCX and CB double-labeled (DCX+CB+) cells were scattered throughout the DG. At P7, DCX+CB+ cells (about 92% of CB+ cells) were seen only in the granule cell layer (GCL) of the dorsal blade. At P14, DCX+CB+ cells (about 66% of CB+ cells) were found in the lower half of the GCL of both blades. In contrast, at P21, about 18% of CB+ cells were DCX+CB+ cells, and they were mainly located only in the subgranular zone of the DG. These results suggest that the developmental pattern of DCX+CB+ cells changes with time in the early postnatal stages.

Differential effects of treadmill exercise on cyclooxygenase-2 in the rat hippocampus at early and chronic stages of diabetes / 한국실험동물학회지

Cyclooxygenase-2 (COX-2) is believed to be a multifunctional neural modulator that affects synaptic plasticity in the hippocampus. In the present study, we investigated the differential effects of treadmill exercise on COX-2 immunoreactivity in the dentate gyrus in early and chronic diabetic stages in Zucker diabetic fatty (ZDF) rats and lean control (ZLC) rats. To this end, ZLC and ZDF rats at 6 or 23 weeks of age were put on a treadmill with or without running for 1 h/day for 5 consecutive days at 16-22 m/min for 5 weeks or 12-16 m/min for 7 weeks, respectively. Treadmill exercise in prediabetic and chronic diabetic rats significantly reduced blood glucose levels. In particular, exercise in the prediabetic rat blocked the onset of diabetes. COX-2 immunoreactivity was mainly detected in the granule cell layer of the dentate gyrus and stratum pyramidale of the CA3 region in all groups. COX-2 immunoreactivity was significantly increased in these regions of ZLC and ZDF rats after treadmill exercise in the early diabetic stage. However, COX-2 immunoreactivity was not changed in these regions in ZDF rats after treadmill exercise in the chronic stage. These results suggest that treadmill exercise in diabetic animals in the chronic stage has limited ability to cause plasticity in the dentate gyrus.

The high dosage of earthworm (Eisenia andrei) extract decreases cell proliferation and neuroblast differentiation in the mouse hippocampal dentate gyrus / 대한해부학회지

Earthworm extract has shown anticancer characteristics. In the present study, we examined the effect of chronic treatment with a high dose of earthworm (Eisenia andrei) extract (EE) on cell proliferation and neuroblast differentiation in the hippocampal dentate gyrus (DG) of 3-week-old mice using 5-bromo-2'-deoxyuridine (BrdU) and Ki-67 immunohistochemistry for cell proliferation and doublecortin (DCX) immunohistochemistry for neuroblast differentiation, respectively. BrdU-, Ki-67-, and DCX-immunoreactive cells were easily detected in the subgranular zone of the DG in vehicle (saline)-treated mice. However, BrdU-, Ki-67-, and DCX-immunoreactive cells in the 500 mg/kg EE-treated mice decreased distinctively compared to those in the vehicle-treated mice. In addition, brain-derived neurotrophic factor (BDNF) immunoreactivity and its protein level decreased markedly in the DG of the EE-treated group compared to those in the vehicle-treated group. These results indicate that chronic treatment with high dose EE decreased cell proliferation and neuroblast differentiation, and that BDNF immunoreactivity decreased in the DG of EE-treated mice.

Neuroprotection of Alpinia katsumadai Seed Extract against Neuronal Damage in the Ischemic Gerbil Hippocampus is Linked to Altered Brain-Derived Neurotrophic Factor / 한국실험동물학회지

The extract of Alpinia katsumadai, a member of the family Zingiberaceae, shows anti-inflammatory effects and antioxidant activity. We observed the neuroprotective effects of the extract from Alpinia katsumadai seed (EAKS) against ischemic damage in gerbils administered oral EAKS (25, and 50 mg/kg) once a day for 7 days before transient cerebral ischemia. In the 50 mg/kg EAKS-treated ischemia group, about 67% of neurons in the hippocampal CA1 region (CA1) survived after ischemia/reperfusion (I/R) based on cresyl violet staining. We observed that EAKS treatment significantly maintained brain-derived neurotrophic factor (BDNF) immunoreactivity in the ischemic CA1 region after I/R. In addition, protein levels of BDNF in the 50 mg/kg EAKS-treated ischemia group were much higher than those in the vehicle-treated ischemia group after I/R. These findings indicate that repeated supplementation of EAKS protects neurons from ischemic damage, such that BDNF is distinctively maintained in ischemic areas.

Effects of repeated restraint stress on platelet endothelial cell adhesion molecule-1 immunoreactivity and protein levels in the gerbil hippocampus after transient cerebral ischemia / 대한해부학회지

Stress has long been known to be a causative factor of various disease states. In this study, we investigated the effects of repeated restraint stress on platelet endothelial cell adhesion molecule-1 (PECAM-1), a very important mediator in inflammation, immunoreactivity and protein levels as well as neuronal damage, in the gerbil hippocampus after 5 minutes of transient cerebral ischemia. Transient ischemia-induced neuronal death was shown in CA1 pyramidal cells 4 days after ischemia/reperfusion. However, repeated restraint stress protected neuronal death induced by ischemic damage. In the ischemia-group, PECAM-1 immunoreactivity and its protein levels were significantly increased in all the hippocampal subregions 4 days after ischemia/reperfusion. However, PECAM-1 immunoreactivity and its protein levels did not change significantly in the hippocampus of the stress-ischemia-group compared to the sham-groups. These results indicate that repeated restraint stress protects neuronal damage induced by transient cerebral ischemia, and this may be associated with maintenance of PECAM-1levels.

Doublecortin-immunoreactive Neuroblasts in Each Layer of the Main Olfactory Bulb After Transient Cerebral Ischemia in Gerbils / 한국실험동물학회지

Neurogenesis in the adult brain occurs continuously throughout life. The main olfactory bulb (MOB) is the first central relay of the olfactory system. We examined proliferation of newly generated cells in each layer of the gerbil MOB after 5 min of transient cerebral ischemia using doublecortin (DCX), a marker of neuronal progenitors. Many DCX immunoreactive neuroblasts were found in the all layers of the MOBs of control and ischemia groups. Ten to 15 days after ischemia/reperfusion, no difference in numbers of DCX immunoreactive neuroblasts was found in the MOB. Thirty days after ischemia/reperfusion, significant increase of DCX immunoreactive cells was observed in all layers of ischemic MOB. This result indicates that neuroblasts increase in the MOB from 30 days after transient cerebral ischemia in gerbils.

Age-related Changes in Doublecortin Immunoreactivity and Its Protein Levels in the Dog Main Olfactory Bulb / 대한해부학회지

Doublecortin (DCX), a microtubule-associated protein, expresses specifically in neuronal precursors and used as a marker for neuronal precursors and neurogenesis. In the present study, we observed differences in DCX immunoreactivity and its protein levels in the main olfactory bulb (MOB) of young adult, middle-aged and aged dogs. In the young adult dog, DCX-immunoreactive cells with well-stained processes were detected in the MOB. DCX immunoreactive cells were decreased in the MOB of middle-aged dog. In the aged dog, DCX immunoreactive cells were more decreased compared to that in the MOB of middle-aged dog. DCX protein level in the dog MOB was also significantly decreased with age. These results suggest that reductions of DCX immunoreactivity and protein levels in the aged MOB may be involved in some neural deficits related to olfactory impairment in the aged dog.