Enhanced autophagy interacting proteins negatively correlated with the activation of apoptosis-related caspase family proteins after focal ischemic stroke of young rats.

BACKGROUND: Neuronal injury induced in young rats by cerebral ischemia reperfusion (CIR) is known to differ substantially from that in adult rats. In the present study, we investigated the specific differences in neuronal injury induced by focal CIR between young and adult rats. RESULTS: 2, 3, 5-triphenyl tetrazolium chloride (TTC) staining revealed a gradual increase in the infarct volume of both young and adult rats in accordance with I/R times and was significantly lower in young rats than in adult rats under the same conditions. The number of cells in the cortex showing immunoreactivity for neuronal nuclei (NeuN) gradually decreased in both young and adult rats in accordance with I/R times; these numbers were significantly higher in young rats than in adult rats under the same conditions. Similarly, as the duration of I/R increased, the degree of glial activation in the cortex penumbra region became more severe in both young and adult groups; however, glial activation was significantly lower in the cortex penumbra region of young rats when compared with that in adult rats. In addition, the expression of Beclin-1 was significantly higher in the infarct penumbra of young rats than adult rats and was more frequently co-expressed with neurons. The levels of autophagy-related proteins increased significantly in the penumbra region after I/R in both young and adult groups, this increase was more pronounced in young rats than in adult rats. Following CIR, analysis revealed significantly lower levels of pro-apoptosis-related factors and significantly higher levels of anti-apoptosis-related proteins in the young rats than in adult rats. CONCLUSIONS: Collectively, the present results suggest that the the reduced levels of neuronal death after CIR in young rats were closely related to enhanced levels of autophagy and reduced levels of pro-apoptosis in neurons.

The Use of Blended Teaching in Higher Medical Education during the Pandemic Era.

Objective: This study aims to compare the effect of blended teaching and traditional teaching in higher medical education during the pandemic era. Methods: Taking the teaching of neurology as an example, 293 Yangzhou University Clinical Medicine 2016 undergraduate students were selected as the research subjects, and were randomly divided into 2 groups a blended teaching group (n = 148) and a traditional teaching group (n = 145), and received blended teaching and traditional teaching, respectively. The blended teaching was based on a Massive Open Online Course, problem-based learning, and case-based learning and supplemented by Tencent video conferences, QQ messaging groups, and other auxiliary teaching tools. At the end of the course, the teaching effect and satisfaction rate were evaluated through theory assessment, practical skills assessment, and an anonymous questionnaire survey. Results: There were significant differences in theoretical achievements (81.83 ± 6.23 vs 76.79 ± 6.87, P < 0.001) and practical skill achievements (84.74 ± 6.50 vs 78.48 ± 6.53, P < 0.001). In addition, significant differences in all aspects of satisfaction rate were observed between the two groups (all P < 0.001). Conclusion: Blended teaching is beneficial to students' learning and stimulates their enthusiasm, cultivates clinical thinking ability, and improves teaching quality. Thus, it has played a positive role in the reform of higher medical teaching during the pandemic era.

Expression of Long Non-coding RNA RGD1566344 in the Brain Cortex of Male Mice After Focal Cerebral Ischemia-Reperfusion and the Neuroprotective Effect of a Non-coding RNA RGD1566344 Inhibitor.

Ischemic stroke (IS) remains a major cause of disability and death. The changes in long non-coding RNA (lncRNA) RGD1566344 expression in the mouse cerebral cortex, including the infarct and penumbra regions after IS, are not clear. Less is known about the impact and underlying mechanisms of RGD1566344 in IS. In this study, we found that RGD1566344 levels were elevated in the ischemic infarct and penumbra regions 12 h after middle cerebral artery occlusion/reperfusion (MCAO/R) in male mice and in PC12 cells with oxygen glucose deprivation/reperfusion (OGD/R). The inhibition of RGD1566344 by small interference RNA (siRNA) significantly alleviated apoptosis in OGD/R PC12 cells. In cell transfection, quantitative real-time PCR, and Western blot experiments, we demonstrated the possible interaction of non-POU domain-containing octamer-binding protein (NONO) with RGD1566344. The NONO level in OGD/R PC12 cells was obviously increased after inhibiting the RGD1566344 treatment; subsequently the protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway was activated. This demonstrated the effect of the RGD1566344-NONO-AKT axis on neural protection after IS. These results revealed a new molecular mechanism of lncRNA RGD1566344 inhibitors through targeting NONO/AKT/mTOR signaling to protect against ischemic neuronal injury, providing strong evidence for the development of promising therapeutic strategies against IS.

Dynamic Changes in miR-126 Expression in the Hippocampus and Penumbra Following Experimental Transient Global and Focal Cerebral Ischemia-Reperfusion.

miR-126 which is considered one of the most important miRNAs for maintaining vascular integrity, plays an important role in neuroprotection after cerebral ischemia-reperfusion (I-R). Moreover, vascular endothelial growth factor A (VEGFA), sprouty-related EVH1 domain-containing protein 1 (SPRED1), and Raf-1 are also involved in physiological processes of vascular endothelial cells (ECs). This study investigated how miR-126 changes with reperfusion time in different brain tissues after global cerebral ischemia and focal cerebral ischemia and examined the underlying mechanism miR-126 involving VEGFA, SPRED1, and Raf-1 after I-R. The results indicated decreases in the levels of miR-126-3p and miR-126-5p expression in mice and gerbils after I-R, consistent with the results after oxygen and glucose deprivation and reperfusion (OGD/R) in PC12 cells. Glial cells were activated as neuronal damage gradually increased after I-R. Inhibition of miR-126-3p exacerbated the OGD/R-induced cell death and reduced cell viability. After miR-126-3p inhibition, the levels of SPRED1 and VEGFA expression were increased, and p-Raf-1 expression was decreased after OGD/R. Moreover, based on the intervention of miR-126-3p inhibition, we found that the expression of p-Raf-1 was significantly increased after the intervention of siSPRED1, while it was not statistically significant after intervention of siVEGFA. The reduction of miR-126 expression after global and focal cerebral ischemia exacerbated neuronal death, which was closely related to increasing the SPRED1 activation and inhibiting the Raf-1 expression.

Therapeutic hypothermia attenuates paraplegia and neuronal damage in the lumbar spinal cord in a rat model of asphyxial cardiac arrest.

Spinal cord ischemia can result from cardiac arrest. It is an important cause of severe spinal cord injury that can lead to serious spinal cord disorders such as paraplegia. Hypothermia is widely acknowledged as an effective neuroprotective intervention following cardiac arrest injury. However, studies on effects of hypothermia on spinal cord injury following asphyxial cardiac arrest and cardiopulmonary resuscitation (CA/CPR) are insufficient. The objective of this study was to examine effects of hypothermia on motor deficit of hind limbs of rats and vulnerability of their spinal cords following asphyxial CA/CPR. Experimental groups included a sham group, a group subjected to CA/CPR, and a therapeutic hypothermia group. Severe motor deficit of hind limbs was observed in the control group at 1 day after asphyxial CA/CPR. In the hypothermia group, motor deficit of hind limbs was significantly attenuated compared to that in the control group. Damage/death of motor neurons in the lumbar spinal cord was detected in the ventral horn at 1 day after asphyxial CA/CPR. Neuronal damage was significantly attenuated in the hypothermia group compared to that in the control group. These results indicated that therapeutic hypothermia after asphyxial CA/CPR significantly reduced hind limb motor dysfunction and motoneuronal damage/death in the ventral horn of the lumbar spinal cord following asphyxial CA/CPR. Thus, hypothermia might be a therapeutic strategy to decrease motor dysfunction by attenuating damage/death of spinal motor neurons following asphyxial CA/CPR.

Both decreased Akt expression and mTOR phosphorylation are related to decreased neuronal differentiation in the hippocampal alveus of aged mice.

BACKGROUND: Aging is an inevitable process which results in many changes. These changes are closely related to the hippocampus which is in charge of long-term learning and episodic memory. AIM: This study was to investigate age-related changes of the cell proliferation, neuroblast differentiation and Akt/mTOR signaling in the hippocampal alveus of aged mice. METHODS: In the present study, we compared the differences of neurogenesis in the hippocampal alveus between adult (postnatal month 6) and aged (postnatal month 24) mice using immunohistochemistry and western blot analysis. RESULTS: The cell proliferation, neuroblast differentiation, and the increased astrocyte activation in the hippocampal alveus of mice were decreased in an age-dependent manner. In addition, during normal aging, the protein level of AKT, mTOR and the phosphorylation of mTOR were all decreased. However, the protein level of AKT was increased. DISCUSSION: These results indicate the neurogenesis in the immature neurons in the hippocampal alveus of aged mice was closely related to the normal aging process. In addition, during normal aging, the increased AKT phosphorylation and decreased mTOR phosphorylation in the hippocampus may play a role in aging development. CONCLUSION: The result indicates that increased activation of astrocyte, increased phosphorylation of AKT and decreased phosphorylation of mTOR may be involved in the decreased cell proliferation and neuroblast differentiation in the alveus of hippocampus of aged mice.

Topiramate Improves Neuroblast Differentiation of Hippocampal Dentate Gyrus in the D-Galactose-Induced Aging Mice via Its Antioxidant Effects.

Some anticonvulsant drugs are associated with cognitive ability in patients; Topiramate (TPM) is well known as an effective anticonvulsant agent applied in clinical settings. However, the effect of TPM on the cognitive function is rarely studied. In this study, we aimed to observe the effects of TPM on cell proliferation and neuronal differentiation in the dentate gyrus (DG) of the D-galactose-induced aging mice by Ki-67 and doublecortin (DCX) immunohistochemistry. The study is divided into four groups including control, D-galactose-treated group, 25 and 50 mg/kg TPM-treated plus D-galactose-treated groups. We found, 50 mg/kg (not 25 mg/kg) TPM treatment significantly increased the numbers of Ki-67+ cells and DCX immunoreactivity, and improved neuroblast injury induced by D-galactose treatment. In addition, we also found that decreased immunoreactivities and protein levels of antioxidants including superoxide dismutase and catalase induced by D-galactose treatment were significantly recovered by 50 mg/kg TPM treatment in the mice hippocampal DG (P < 0.05). In conclusion, our present results indicate that TPM can ameliorate neuroblast damage and promote cell proliferation and neuroblast differentiation in the hippocampal DG via increasing SODs and catalase levels in the D-galactose mice.

Increases of Catalase and Glutathione Peroxidase Expressions by Lacosamide Pretreatment Contributes to Neuroprotection Against Experimentally Induced Transient Cerebral Ischemia.

Lacosamide is a new antiepileptic drug which is widely used to treat partial-onset seizures. In this study, we examined the neuroprotective effect of lacosamide against transient ischemic damage and expressions of antioxidant enzymes such as Zn-superoxide dismutase (SOD1), Mn-superoxide dismutase (SOD2), catalase (CAT) and glutathione peroxidase (GPX) in the hippocampal cornu ammonis 1 (CA1) region following 5 min of transient global cerebral ischemia in gerbils. We found that pre-treatment with 25 mg/kg lacosamide protected CA1 pyramidal neurons from transient global cerebral ischemic insult using hematoxylin-eosin staining and neuronal nuclear antigen immunohistochemistry. Transient ischemia dramatically changed expressions of SOD1, SOD2 and GPX, not CAT, in the CA1 pyramidal neurons. Lacosamide pre-treatment increased expressions of CAT and GPX, not SOD1 and 2, in the CA1 pyramidal neurons compared with controls, and their expressions induced by lacosamide pre-treatment were maintained after transient cerebral ischemia. In brief, pre-treatment with lacosamide protected hippocampal CA1 pyramidal neurons from ischemic damage induced by transient global cerebral ischemia, and the lacosamide-mediated neuroprotection may be closely related to increases of CAT and GPX expressions by lacosamide pre-treatment.

Neuroprotection of posttreatment with risperidone, an atypical antipsychotic drug, in rat and gerbil models of ischemic stroke and the maintenance of antioxidants in a gerbil model of ischemic stroke.

Risperidone, an atypical antipsychotic drug, has been discovered to have some beneficial effects beyond its original effectiveness. The present study examines the neuroprotective effects of risperidone against ischemic damage in the rat and gerbil induced by transient focal and global cerebral ischemia, respectively. The results showed that pre- and posttreatment with 4 mg/kg risperidone significantly protected against neuronal death from ischemic injury. Many NeuN-immunoreactive neurons and a few F-J B-positive cells were found in the rat cerebral cortex and gerbil hippocampal CA1 region (CA1) in the risperidone-treated ischemia groups compared with those in the vehicle-treated ischemia group. In addition, treatment with risperidone markedly attenuated the activation of microglia in the gerbil CA1. On the other hand, we found that treatment with risperidone significantly maintained the antioxidants levels in the ischemic gerbil CA1. Immunoreactivities of superoxide dismutases 1 and 2, catalase, and glutathione peroxidase were maintained in the stratum pyramidale of the CA1; the antioxidants were very different from those in the vehicle-treated ischemia groups. In brief, our present findings indicate that posttreatment as well as pretreatment with risperidone can protect neurons in the rat cerebral cortex and gerbils CA1 from transient cerebral ischemic injury and that the neuroprotective effect of risperidone may be related to attenuation of microglial activation as well as maintenance of antioxidants.

Effects of high-fat diet on neuronal damage, gliosis, inflammatory process and oxidative stress in the hippocampus induced by transient cerebral ischemia.

In this study, we investigated the effects of a normal diet (ND) and high-fat diet (HFD) on delayed neuronal death in the gerbil hippocampal CA1 region after transient cerebral ischemia. In the HFD-fed gerbils, ischemia-induced hyperactivity was significantly increased and neuronal damage was represented more severely compared to the ND-fed gerbils. Ischemia-induced glial activation was accelerated in the HFD-fed gerbils. Cytokines including interleukin-2 and -4 were more sensitive in the hippocampal CA1 region of the HFD-fed gerbils after ischemia-reperfusion. Additionally, we found that decreased 4-HNE and SODs immunoreactivity and protein levels in the hippocampal CA1 region of the HFD-fed gerbils after ischemia-reperfusion. These results indicate that HFD may lead to the exacerbated effects on ischemia-induced neuronal death in the hippocampal CA1 region after ischemia-reperfusion. These effects of HFD may be associated with more accelerated activations of glial cells and imbalance of pro- and anti-inflammatory cytokines and/or antioxidants after transient cerebral ischemia.

Decreased insulin-like growth factor-I and its receptor expression in the hippocampus and somatosensory cortex of the aged mouse.

Insulin-like growth factor-I (IGF-I) is a multifunctional polypeptide and has diverse effects on brain functions. In the present study, we compared IGF-I and IGF-I receptor (IGF-IR) immunoreactivity and their protein levels between the adult (postnatal month 6) and aged (postnatal month 24) mouse hippocampus and somatosensory cortex. In the adult hippocampus, IGF-I immunoreactivity was easily observed in the pyramidal cells of the stratum pyramidale in the hippocampus proper and in the granule cells of the granule cell layer of the dentate gyrus. In the adult somatosensory cortex, IGF-I immunoreactivity was easily found in the pyramidal cells of layer V. In the aged groups, IGF-I expression was dramatically decreased in the cells. Like the change of IGF-I immunoreactivity, IGF-IR immunoreactivity in the pyramidal and granule cells of the hippocampus and in the pyramidal cells of the somatosensory cortex was also markedly decreased in the aged group. In addition, both IGF-I and IGF-IR protein levels were significantly decreased in the aged hippocampus and somatosensory cortex. These results indicate that the apparent decrease of IGF-I and IGF-IR expression in the aged mouse hippocampus and somatosensory cortex may be related to age-related changes in the aged brain.

Anti-inflammatory effect of tanshinone I in neuroprotection against cerebral ischemia-reperfusion injury in the gerbil hippocampus.

Tanshinone I (TsI) is an important lipophilic diterpene extracted from Danshen (Radix Salvia miltiorrhizae) and has been used in Asia for the treatment of cerebrovascular diseases such as ischemic stroke. In this study, we examined the neuroprotective effect of TsI against ischemic damage and its neuroprotective mechanism in the gerbil hippocampal CA1 region (CA1) induced by 5 min of transient global cerebral ischemia. Pre-treatment with TsI protected pyramidal neurons from ischemic damage in the stratum pyramidale (SP) of the CA1 after ischemia-reperfusion. The pre-treatment with TsI increased the immunoreactivities and protein levels of anti-inflammatory cytokines [interleukin (IL)-4 and IL-13] in the TsI-treated-sham-operated-groups compared with those in the vehicle-treated-sham-operated-groups; however, the treatment did not increase the immunoreactivities and protein levels of pro-inflammatory cytokines (IL-2 and tumor necrosis factor-α). On the other hand, in the TsI-treated-ischemia-operated-groups, the immunoreactivities and protein levels of all the cytokines were maintained in the SP of the CA1 after transient cerebral ischemia. In addition, we examined that IL-4 injection into the lateral ventricle did not protect pyramidal neurons from ischemic damage. In conclusion, these findings indicate that the pre-treatment with TsI can protect against ischemia-induced neuronal death in the CA1 via the increase or maintenance of endogenous inflammatory cytokines, and exogenous IL-4 does not protect against ischemic damage.

Comparison of neuroprotective effects of extract and fractions from Agarum clathratum against experimentally induced transient cerebral ischemic damage.

UNLABELLED: CONTEXTS: Agarum clathratum (Laminariaceae), a typical brown algae, has been identified by National Plant Quarantine Service in Korea. The extract of A. clathratum has antioxidant activities. OBJECTIVE: We investigated the neuroprotective effects of crude-extract, ethyl acetate (EA)-, n-butanol (BU)-, dichloromethane (DCM)- and n-hexane (Hx)-fractions from A. clathratum on ischemic damage in the gerbil hippocampal CA1 region (CA1) after 5 min of transient cerebral ischemia. MATERIALS AND METHODS: Agarum clathratum was collected in Kangwon province (South Korea) and treated with 95% ethanol. The ethanol extract was suspended in distilled water and subjected to a series of partitions with EA, BU, DCM and Hx. Each of extract and fraction was orally administered with 50 mg/kg once a day for one week before ischemia--reperfusion (I-R). RESULT: In the crude-extract-, EA- and BU-fraction-treated ischemia groups, we found strong neuroprotection in the CA1--about 80-89% of CA1 pyramidal neurons survived. However, in the DCM- and Hx-fraction-treated ischemia groups, we did not find any significant neuroprotection. In addition, we observed changes in astrocytes and microglia in the ischemic CA1. In the crude-extract, EA- and BU-fraction-treated ischemia groups, the distribution pattern and activity of the glial cells were similar to that found in the sham group. DISCUSSION: Repeated supplements of crude-extract, EA- and BU-fractions of A. clathratum could protect neurons from I-R injury in the hippocampal CA1 induced by transient cerebral ischemia via decrease of glial activation.

Comparison of α-synuclein immunoreactivity in the hippocampus between the adult and aged beagle dogs.

Alpha-synuclein (α-syn), as a neuroprotein, is expressed in neural tissue, and it is related to a synaptic transmission and neuronal plasticity. In this study, we compared the distribution and immunoreactivity of α-syn and related gliosis in hippocampus between young adult (2-3 years) and aged (10-12 years) beagle dogs. In both groups, α-syn immunoreactivity was detected in neuropil of all the hippocampal sub-regions, but not in neuronal somata. In the aged hippocampus, α-syn immunoreactivity was apparently increased in mossy fibers compared to that in the adult dog. In addition, α-syn protein level was markedly increased in the aged hippocampus. On the other hand, GFAP and Iba-1 immunoreactivity in astrocytes and microglia, respectively, were increased in all the hippocampal sub-regions of the aged group compared to that in the adult group: especially, their immunoreactivity was apparently increased around mossy fibers. In addition, in this study, we could not find any expression of α-syn in astrocytes and microglia. These results indicate that α-syn immunoreactivity apparently increases in the aged hippocampus and that GFAP and Iba-1 immunoreactivity are also apparently increased at the regions with increased α-syn immunoreactivity. This increase in α-syn expression might be a feature of normal aging.

Neuronal damage using fluoro-Jade B histofluorescence and gliosis in the gerbil septum submitted to various durations of cerebral ischemia.

The extent of neuronal damage/death in some brain regions is highly correlated to duration time of transient ischemia. In the present study, we carried out neuronal degeneration/death and glial changes in the septum 4 days after 5, 10, 15, and 20 min of transient cerebral ischemia using gerbils. To examine neuronal damage, Fluoro-Jade B (F-J B, a marker for neuronal degeneration) histofluorescence staining was used. F-J B positive ((+)) cells were detected in the septo-hippocampal nucleus (SHN) of the septum only in the 20 min ischemia-group; the mean number of F-J B(+) neurons was 14.9 ± 2.5/400 µm(2) in a section. Gliosis of astrocytes and microglia was examined using anti-glial fibrillary acidic protein (GFAP) and anti-ionized calcium-binding adapter molecule 1 (Iba-1), respectively. In all the ischemia-groups, GFAP- and Iba-1-immunoreactive astrocytes and microglia, respectively, were increased in number, and apparently tended to be increased in their immunoreactivity. Especially, in the 20 min ischemia-group, the number and immunoreactivity of Iba-immunoreactive microglia was highest and strongest in the ischemic SHN 4 days after ischemia-reperfusion. In brief, our findings showed that neuronal damage/death in the SHN occurred and gliosis was apparently increased in the 20 min ischemia-group at 4 days after ischemia-reperfusion.

Comparison of expression of inflammatory cytokines in the spinal cord between young adult and aged beagle dogs.

Aging is an inevitable process that occurs in the whole body system accompanying with many functional and morphological changes. Inflammation is known as one of age-related factors, and inflammatory changes could enhance mortality risk. In this study, we compared immunoreactivities of inflammatory cytokines, such as interleukin (IL)-2 (a pro-inflammatory cytokine), its receptor (IL-2R), IL-4 (an anti-inflammatory cytokine), and its receptor (IL-4R) in the cervical and lumbar spinal cord of young adult (2-3 years old) and aged (10-12 years old) beagle dogs using immunohistochemistry and western blotting. IL-2 and IL-2R-immunoreactive nerve cells were found throughout the gray matter of the cervical and lumbar spinal cord of young adult and aged dogs. In the spinal cord neurons of the aged dog, immunoreactivity and protein levels were apparently increased compared with those in the young adult dog. Change patterns of IL-4- and IL-4R-immunoreactive cells and their protein levels were also similar to those in IL-2 and IL-2R; however, IL-4 and IL-4R immunoreactivity in the periphery of the neuronal cytoplasm in the aged dog was much stronger than that in the young adult dog. These results indicate that the increase of inflammatory cytokines and their receptors in the aged spinal cord might be related to maintaining a balance of inflammatory reaction in the spinal cord during normal aging.

Time-course changes in immunoreactivities of glucokinase and glucokinase regulatory protein in the gerbil hippocampus following transient cerebral ischemia.

Glucose is a main energy source for normal brain functions. Glucokinase (GK) plays an important role in glucose metabolism as a glucose sensor, and GK activity is modulated by glucokinase regulatory protein (GKRP). In this study, we examined the changes of GK and GKRP immunoreactivities in the gerbil hippocampus after 5 min of transient global cerebral ischemia. In the sham-operated-group, GK and GKRP immunoreactivities were easily detected in the pyramidal neurons of the stratum pyramidale of the hippocampus. GK and GKRP immunoreactivities in the pyramidal neurons were distinctively decreased in the hippocampal CA1 region (CA), not CA2/3, 3 days after ischemia-reperfusion (I-R). Five days after I-R, GK and GKRP immunoreactivities were hardly detected in the CA1, not CA2/3, pyramidal neurons; however, at this point in time, GK and GKRP immunoreactivities were newly expressed in astrocytes, not microglia, in the ischemic CA1. In brief, GK and GKRP immunoreactivities are changed in pyramidal neurons and newly expressed in astrocytes in the ischemic CA1 after transient cerebral ischemia. These indicate that changes of GK and GKRP expression may be related to the ischemia-induced neuronal damage/death.

Reduced beta-catenin expression in the hippocampal CA1 region following transient cerebral ischemia in the gerbil.

Beta-catenin, a transcription factor, plays a critical role in cell survival and degradation after stroke. In this study, we examined changes of expression in beta-catenin in the hippocampal CA1 region of the gerbil following 5 min of transient cerebral ischemia. We observed neuronal damage using cresyl violet staining, neuronal nuclei immunohistochemistry and Fluro-Jade B immunofluorescence. Four days after ischemia-reperfusion (I-R), most of pyramidal cells in the CA1 region were damaged. In addition, early damage in dendrites was detected 1 day after I-R by immunohistochemical staining for microtubule-associated protein 2 (MAP-2), and MAP-2 immunoreactivity was hardly detected in the CA1 region 4 days after I-R. We found that beta-catenin (a synapse-enriched cell adhesion molecule) was well expressed in dendrites before I-R. Its immunoreactivity was well colocalized with MAP-2. Chronological change of beta-catenin immunoreactivity was novelty in the present study. Twelve hours after I-R, its immunoreactivity was decreased in the stratum radiatum of the CA1 region, however, its immunoreactivity was increased 1 and 2 days after I-R, and decreased sharply 4 days after I-R. However, we did not find any change in beta-catenin immunoreactivity in the CA2 and CA3 region. In brief, we suggest that early change of beta-catenin expression in the stratum pyramidale of ischemic hippocampal CA1 region is associated with early dendrite damage following transient cerebral ischemia.

Effects of transient cerebral ischemia on the expression of DNA methyltransferase 1 in the gerbil hippocampal CA1 region.

DNA methylation is a key epigenetic modification of DNA that is catalyzed by DNA methyltransferases (Dnmt). Increasing evidences suggest that DNA methylation in neurons regulates synaptic plasticity as well as neuronal network activity. In the present study, we investigated the changes in DNA methyltransferases 1 (Dnmt1) immunoreactivity and its protein levels in the gerbil hippocampal CA1 region after 5 min of transient global cerebral ischemia. CA1 pyramidal neurons were well stained with NeuN (a neuron-specific soluble nuclear antigen) antibody in the sham-group, Four days after ischemia-reperfusion (I-R), NeuN-positive ((+)) cells were significantly decreased in the stratum pyramidale (SP) of the CA1 region, and many Fluro-Jade B (a marker for neuronal degeneration)(+) cells were observed in the SP. Dnmt1 immunoreactivity was well detected in all the layers of the sham-group. Dnmt1 immunoreactivity was hardly detected only in the stratum pyramidale of the CA1 region from 4 days post-ischemia; however, at these times, Dnmt1 immunoreactivity was newly expressed in GABAergic interneurons or astrocytes in the ischemic CA1 region. In addition, the level of Dnmt1 was lowest at 4 days post-ischemia. In brief, both the Dnmt1 immunoreactivity and protein levels were distinctively decreased in the ischemic CA1 region 4 days after transient cerebral ischemia. These results indicate that the decrease of Dnmt1 expression at 4 days post-ischemia may be related to ischemia-induced delayed neuronal death.

Aripiprazole, an atypical antipsychotic drug, improves maturation and complexity of neuroblast dendrites in the mouse dentate gyrus via increasing superoxide dismutases.

Apripiprazole (APZ) is well known as an atypical antipsychotic and antidepressant. In the present study, we investigated effects of APZ on cell proliferation and neuronal differentiation in the dentate gyrus (DG) of the adolescent mouse using BruU, Ki-67 and doublecortin (DCX) immunohistochemistry. BruU, Ki-67 and DCX-positive (+) cells were easily detected in the subgranular zone of the DG in the vehicle- and APZ-treated group. We found that in the 8 mg/kg APZ-treated group numbers of Ki-67(+), DCX(+) and BrdU(+)/DCX(+) cells were significantly increased compared with those in the vehicle-treated group. We also found that maturation and complexity of DCX(+) dendrites in the 8 mg/kg APZ-treated group was well improved compared with those in the vehicle-treated group. In addition, markedly decreased lipid peroxidation and increased superoxide dismutase 2 (SOD2) level were observed in the DG of the 8 mg/kg APZ-treated group. Our present findings indicate that APZ can enhance cell proliferation and neuroblast differentiation, particularly maturation and complexity of neuroblast dendrites, in the DG via decreasing lipid peroxidation and increasing SOD2 level.