Neuronal Apoptosis In Rats Research Articles

Neuroprotective Effects of Ginsenoside-Rg1 Against Depression-Like Behaviors via Suppressing Glial Activation, Synaptic Deficits, and Neuronal Apoptosis in Rats.

Depression is considered a neuropsychiatric disease associated with various neuronal changes within specific brain regions. We previously reported that ginsenoside-Rg1, a potential neuroprotective agent extracted from ginseng, significantly alleviated depressive-like disorders induced by chronic stress in rats. However, the mechanisms by which ginsenoside-Rg1 exerts its neuroprotective effects in depression remain largely uncharacterized. In the present study we confirm that ginsenoside-Rg1 significantly prevented the antidepressant-like effects in a rat model of chronic unpredictable mild stress (CUMS) and report on some of the underlying mechanisms associated with this effect. Specifically, we found that chronic pretreatment with ginsenoside-Rg1 prior to stress exposure significantly suppressed inflammatory pathway activity via alleviating the overexpression of proinflammatory cytokines and the activation of microglia and astrocytes. These effects were accompanied with an attenuation of dendritic spine and synaptic deficits as associated with an upregulation of synaptic-related proteins in the ventral medial prefrontal cortex (vmPFC). In addition, ginsenoside-Rg1 inhibited neuronal apoptosis induced by CUMS exposure, increased Bcl-2 expression and decreased cleaved Caspase-3 and Caspase-9 expression within the vmPFC region. Furthermore, ginsenoside-Rg1 could increase the nuclear factor erythroid 2-related factor (Nrf2) expression and inhibit p38 mitogen-activated protein kinase (p-p38 MAPK) and nuclear factor κB (NF-κB) p65 subunit activation within the vmPFC. Taken together, these results suggest that the neuroprotective effects of ginsenoside-Rg1, which may assume the antidepressant-like effect in this animal model of depression, appears to result from amelioration of a CUMS-dependent neuronal deterioration within the vmPFC. Moreover, they also provide support for the therapeutic potential of ginsenoside-Rg1 in the treatment of stress-related mental disorders.

Silencing of long noncoding RNA MEG3 enhances cerebral protection of dexmedetomidine against hypoxic-ischemic brain damage in neonatal mice by binding to miR-129-5p.

Hypoxic-ischemic brain damage (HIBD) is a leading cause of neonatal acute mortality and chronic nervous system injury. Recently, it has been found that long noncoding RNAs (lncRNAs) play a significant role in the neurodevelopment and etiopathogenesis of HIBD. Here, the researchers aimed to determine the role of lncRNA maternally expressed gene (MEG3) in the therapeutic effect of dexmedetomidine (DEX) in neonatal mice with HIBD through the regulation of microRNA-129-5p (miR-129-5p). HIBD models were established in C57/BL6 neonatal mice. Subsequently, the target relationship between MEG3 and miR-129-5p was predicted and verified. The neonatal mice were injected with DEX, ad-shMEG3, and mimics and inhibitors of miR-129-5p to identify roles of MEG3 and miR-129-5p in therapeutic effects of DEX on neuronal apoptosis and injury, cerebral atrophy, and learning and memory ability of neonatal mice with HIBD. MEG3 directly targeted and inhibited the expression of miR-129-5p. Silencing of MEG3 or upregulation of miR-129-5p effectively promoted the therapeutic effect of DEX on neonatal mice with HIBD. Silencing of MEG3 or upregulation of miR-129-5p reduced the neuronal apoptosis rate and degree of cerebral atrophy, and also enhanced the learning and memory ability of HIBD neonatal mice. Collectively, the key findings obtained from the present study support the notion that MEG3 silencing enhances the therapeutic effect of DEX on neonatal mice with HIBD by binding to miR-129-5p.

Acteoside Attenuates Oxidative Stress and Neuronal Apoptosis in Rats with Focal Cerebral Ischemia-Reperfusion Injury.

Acteoside (ACT) has been shown to exert antioxidant and neuroprotective effects in neurodegenerative diseases. However, the effect of ACT on cerebral ischemia-reperfusion (I/R) injury is not yet clear. In this study, we found that ACT administration reduced infarct volume and brain edema, and improved neurological deficits, as indicated by the decreased modified neurological severity score. Administration of ACT strikingly reduced oxidative stress, accompanied by decreased levels of reactive oxygen species and malondialdehyde and increased levels of superoxide dismutase and catalase in a rat model of middle cerebral artery occlusion/reperfusion (MCAO/R). Furthermore, ACT administration reduced the number of terminal deoxynucleotidyl transferase uridine 5'-triphosphate (UTP) nick-end labeling-positive cells in the cerebral cortex of ischemic side of MCAO/R rats, accompanied by downregulation of B cell lymphoma 2 (Bcl-2) associated X protein and cleaved caspase-3 proteins and upregulation of Bcl-2 protein. Additionally, ACT treatment inhibited the protein kinase R/eukaryotic initiation factor-2α stress pathway in the brains of MCAO/R rats. Our results demonstrated that ACT attenuates oxidative stress and neuronal apoptosis in MCAO/R rats, suggesting that ACT may serve as a novel therapeutic candidate for the treatment of I/R brain injury.

Effect of acupuncture on cholinergic anti-inflammatory pathway in hippocampus of aged rats during global cerebral ischemia-reperfusion

Objective To investigate the effect of acupuncture on cholinergic anti-inflammatory pathway in the hippocampus of aged rats during global cerebral ischemia-reperfusion (I/R). Methods Ninety-six clean-grade healthy male Sprague-Dawley rats, aged 17-22 months, weighing 440-580 g, were divided into 3 groups (n=32 each) using a random number table method: sham operation group (group S), global cerebral I/R group (group I/R) and acupuncture group (group AP). Global cerebral I/R was induced by 4-vessel occlusion method described by Pulsinelli in group I/R and group AP.Baihui and Fengchi were stimulated for 14 consecutive days before ischemia in group AP.Four rats were sacrificed at 1, 3, 5 and 7 days of reperfusion, and brains were removed for determination of neuronal apoptosis by TUNEL.Four rats were sacrificed at 1, 3, 5 and 7 days of reperfusion, and brains were removed for determination of the expression of α7 nicotinic acetylcholine receptor (α7nAChR), choline acetyltransferase (ChAT), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in the hippocampal CA1 region by Western blot.The apoptosis rate was calculated. Results Compared with group S, the apoptosis rate of hippocampal neurons was significantly increased, and the expression of α7nAChR, ChAT, TNF-α and IL-1β was up-regulated at each time point of reperfusion in I/R and AP groups (P<0.05). Compared with group I/R, the apoptosis rate of hippocampal neurons was significantly decreased, the expression of α7nAChR and ChAT was up-regulated, and the expression of TNF-α and IL-1β was down-regulated at each time point of reperfusion in group AP (P<0.05). Conclusion The mechanism by which acupuncture mitigates global cerebral I/R injury may be related to activating cholinergic anti-inflammatory pathway in the hippocampus of aged rats. Key words: Acupuncture; Reperfusion injury; Brain; Aged; Cholinergic anti-inflammatory pathway

Effect of icariin on apoptosis in hippocampal neurons cultured in high glucose

OBJECTIVETo investigate effect of icariin on apoptosis in hippocampal neurons cultured in high glucose, and the possible mechanism behind the action. METHODSHippocampus was obtained from newborn 24 h Sprague-Dawley rats and then primarily cultured. Then hippocampal neurons were divided into normal control group, high glucose group, icariin group, icariin + protein kinase B (Akt) inhibitor group and Akt agonist group. After each group was cultured in different conditioned medium for 72 h, we detected the apoptosis of neurons with flow cytometry, and the expression of Akt, p-Akt, B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein (Bax) with western blot. RESULTSCompared with the normal control group, the apoptosis rate of hippocampal neurons increased significantly (P < 0.01), and p-Akt/Akt and Bcl-2/Bax decreased significantly (P < 0.01) in high glucose group. Compared with the high glucose group, the apoptosis rate of hippocampal neurons decreased significantly (P < 0.01), and p-Akt/Akt and Bcl-2/Bax increased significantly (P < 0.05) in icariin group and Akt agonist group. Compared with the icariin + Akt inhibitor group, the apoptosis rate of hippocampal neurons decreased significantly (P < 0.01), and p-Akt/Akt and Bcl-2/Bax increased significantly (P < 0.01) in icariin group. CONCLUSIONIcariin could reduce the apoptosis of neurons cultured in high glucose, which may be achieved by increasing the phosphorylation of Akt protein in Akt signal pathway, then increasing the expression of Bcl-2 and inhibiting the expression of Bax.

Liraglutide Protects Neurite Outgrowth of Cortical Neurons Under Oxidative Stress though Activating the Wnt Pathway

BackgroundNeurogenesis including neurite outgrowth is important for brain plasticity under physiological conditions and in brain repair after injury. Liraglutide has been found to have neuroprotective action in the risk of central nervous system disease. However, the effect and the potential mechanism of liraglutide-induced neurite outgrowth in primary cortical neurons under oxidative stress remain poorly documented. MethodsIn the text, H2O2 was used to mimic ischemia injury in primary cortical neurons. The viability and apoptosis of cell was assessed by Cell Counting Kit-8 and Hoechst 33342. Immunofluorescence method was used to examine the effect of liraglutide on neurite outgrowth in cortical neuron under H2O2 condition. Then, the potential mechanisms involving the Wnt pathway were investigated. The expression of β-catenin, c-myc, and cyclin D1 was determined using quantitative real-time polymerase chain reaction and Western blot. ResultsLiraglutide significantly increased the viability and alleviated the apoptosis rate of cortical neurons induced by H2O2. Next, liraglutide promoted neurite outgrowth, which could be partially inhibited by the Wnt pathway inhibitor Xav939. Besides, liraglutide induced an increase of β-catenin, c-myc, and cyclin D1 levels, which could also be blocked in the presence of Xav939. ConclusionsThese results illustrate that liraglutide exerts neurotrophin-like activity in cortical neurons under oxidative stress condition, partly through activating the Wnt pathway.

The role of TLR4/P38/JNK signaling pathway in apoptosis of hippocampal neurons

To investigate the effects of the Toll like receptor 4 (TLR4) -P38-JNK signaling pathway in the apoptosis of hippocampal neurons in rats and its mechanisms. And to provide new experimental evidences for the pathogenesis research, prevention and treatment of neurodegenerative diseases (ND). The hippocampal neurons derived from newborn rat were cultured for 7 d in vitro. The purity of hippocampal neurons was identified by immunofluorescence method. In order to activate or block the action of TLR4, the hippocampal neurons were pretreated with TLR4 ligand lipopolysaccharide (LPS) or TLR4 antibody. In the experiment 1, the hippocampal neurons were divided into normal control group, LPS group and TLR4 antibody+LPS group. The expressions of P-P38 and P-JNK were deteced by immunofluorescence. In the experiment 2, the hippocampal neurons were divided into 6 groups:normal control group, LPS group, TLR4 antibody +LPS group, SB202190(inhibitor P38)+LPS group, SP600125(inhibitor JNK)+LPS group, PD98059(inhibitor ERK)+LPS group. The cells in above mentioned groups were pretreated with TLR4 antibody, the inhibitors of P38, JNK or ERK for 2 h respectively. Then, all the six groups were stimulated by LPS for 24 h. The expressions of Bcl-2, Bax and Active-caspase-3 were detected by Western blot. The hippocampal neuronal apoptosis rate were tested with flow cytometry. The expressions of P-P38 and P-JNK of hippocampal neurons in LPS group were higher than those in normal control group (P<0.01). Compared with LPS group, the expressions of P-P38 and P-JNK were decreased significantly in TLR4 antibody +LPS group (P<0.01). Compared with the normal control group, the expressions of Bcl-2/Bax were decreased, while the expression of Active-caspase-3 was increased in the hippocampal neurons after LPS stimulation (P<0.01). The apoptotic rate of hippocampal neurons was higher in LPS group than that in the control group (P<0.01). Compared with LPS group, the expressions of Bcl-2/Bax were increasd and the expression of Active-caspase-3 was decreased in TLR4 antibody+LPS group, SB202190+LPS group, and SP600125+LPS group. The apoptotic rate of hippocampal neurons was significantly lower than that in the LPS group (P<0.05, P<0.01). The cell apoptosis rate had no significant differences between PD98059+LPS group and LPS group. ①TLR4-mediated P38/JNK signaling pathway exists in hippocampal neurons. ②After TLR4 activation in hippocampal neurons, the expressions of P-P38 and P-JNK are up-regulated, the expressions of Bcl-2/Bax are decreased and the expression of Active-caspase-3 is increased, which promote apoptosis of hippocampal neurons. TLR4/P38/JNK signaling pathway is involved in apoptosis of hippocampal neurons.

Effects of Huangpu Tongqiao capsule on apoptosis of Alzheimer's disease cell model

The loss of hippocampal neurons is one of the main pathological features of Alzheimer's disease (AD), which is related to the apoptosis of hippocampal neurons. Huangpu Tongqiao capsule is used for the treatment of AD, but the underlying mechanism is still unclear. This study is to investigate the mechanism of neuroprotective effect of Huangpu Tongqiao capsule in the treatment of AD, through observing the effect of Huangpu Tongqiao capsule containing serum on cell injury of primary cultured hippocampal neurons induced by Aβ₂₅₋₃₅ via inhibiting the cell apoptosis. Primary cultured hippocampal neurons were cultured and identified by MAP-2 immunofluorescence staining, and cell growth state was observed by inverted microscope. The Huangpu Tongqiao capsule containing serum was prepared using the method of serum pharmacology. MTT assays were used to measure the optimum concentration range of Huangpu Tongqiao capsule containing serum, and optimum Aβ concentration for establishing the AD model. After primary cultured hippocampal neurons AD cell model was induced by Aβ₂₅₋₃₅, cell survival rate was detected by MTT, cell apoptosis rate was assayed by flow cytometry, and protein expressions of Bax, Cyt C and caspase-3 were determined by Western blot analysis. The results showed that the primary cultured hippocampal neurons were cultured successfully, and cells grew mature at seventh days; Compared with normal group, the survival rate of hippocampal neurons in AD cell model group was decreased, the apoptosis rate of hippocampal neurons was increased, and the protein expressions of Bax, Cyt C and caspase-3 were increased (P<0.05, P<0.01); Compared with AD cell model group, the survival rate of hippocampal neurons in Huangpu Tongqiao capsule containing serum group was increased, the apoptosis rate of hippocampal neurons was decreased, and the protein expressions of Bax, Cyt C and caspase-3 were decreased (P<0.05, P<0.01). These findings suggest that Huangpu Tongqiao capsule containing serum has a neuroprotective effect on cell injury of the primary cultured hippocampal neurons induced by Aβ₂₅₋₃₅, and its effect on the treatment of AD is associated with the inhibition the apoptosis of hippocampal neurons.

Downregulated expression of microRNA-329 inhibits apoptosis of nigral dopaminergic neurons by regulating CDKN2D expression via the FoxO3a signaling pathway in rats with Parkinson's disease.

Parkinson's disease (PD) is a common neurodegenerative disorder due to the loss of dopaminergic neurons in the substantia nigra. This study focuses on the effect of microRNA-329 (miR-329) on nigral dopaminergic neurons in a rat model of PD via the FoxO3a signaling pathway by binding to CDKN2D. Brain tissues from the substantia nigra were taken from the rats in two groups. TUNEL staining was used to observe tyrosine hydroxylase (TH)-positive neurons. Nigral dopaminergic neurons were randomized into the normal, blank, negative control (NC), miR-329 mimics, miR-329 inhibitors, small interfering (siRNA)-CDKN2D, and miR-329 inhibitors + siRNA-CDKN2D groups. Expressions of miR-329, CDKN2D, FoxO3a, AKT, caspase-3 and Bcl-2 were determined using RT-qPCR and western blotting. Apoptosis rate of nigral dopaminergic neurons in 7 groups was determined by flow cytometry. Compared with the blank and NC groups, the miR-329 mimics group showed increased miR-329 and caspase-3 expressions as well as decreased expressions of CDKN2D, FoxO3a, AKT, and Bcl-2, the siRNA-CDKN2D group indicated enhanced expressions of caspase-3 and declined expressions of CDKN2D, FoxO3a, AKT, and Bcl-2, and the miR-329 inhibitors group revealed decreased miR-329 and caspase-3 expressions and increased expressions of CDKN2D, FoxO3a, AKT, and Bcl-2. The apoptosis rate of nigral dopaminergic neurons was significantly increased in the miR-329 mimics and siRNA-CDKN2D groups, but was decreased in the miR-329 inhibitors group. Our data suggested that downregulated miR-329 could inhibit apoptosis of nigral dopaminergic neurons in a rat model of PD by upregulating the expression of CDKN2D via the activation of the FoxO3a signaling pathway.

RETRACTED ARTICLE: Effects of CREB1 gene silencing on cognitive dysfunction by mediating PKA-CREB signaling pathway in mice with vascular dementia

BackgroundAs a form of dementia primarily affecting the elderly, vascular dementia (VD) is characterized by changes in the supply of blood to the brain, resulting in cognitive impairment. The aim of the present study was to explore the effects involved with cyclic adenosine monophosphate (cAMP) response element-binding (CREB)1 gene silencing on cognitive dysfunction through meditation of the protein kinase A (PKA)-CREB signaling pathway in mice with VD.MethodsBoth the Morris water maze test and the step down test were applied to assess the cognitive function of the mice with VD. Immunohistochemical and TUNEL staining techniques were employed to evaluate the positive expression rates of the protein CREB1 and Cleaved Caspase-3, as well as neuronal apoptosis among hippocampal tissues in a respective manner. Flow cytometry was applied to determine the proliferation index and apoptosis rate of the hippocampal cells among each group. Reverse transcription quantitative polymerase chain reaction and Western blot analysis methods were applied to detect the expressions of cAMP, PKA and CREB in hippocampal cells.ResultsCompared with the normal group, all the other groups exhibited impaired cognitive function, reduced cell numbers in the CAI area, positive expressions of CREB1 as well as positive optical density (OD) values. Furthermore, increased Cleaved Caspase-3 positive expression, OD value, proliferation index, apoptosis rate of hippocampal cells and neurons, were observed in the other groups when compared with the normal group, as well as lower expressions of cAMP, PKA and CREB1 and p-CREB1 (the shCREB1–1, H89 and shCREB1–1 + H89 groups < the VD group).ConclusionThe key findings of the present study demonstrated that CREB1 gene silencing results in aggravated VD that occurs as a result of inhibiting the PKA-CREB signaling pathway, thus exasperating cognitive dysfunction.

Correlations of neuronal apoptosis with expressions of c-Fos and c-Jun in rats with post-ischemic reconditioning damage.

Transcription factors (c-Fos and c-Jun) have been considered to play roles in the initiation of programmed nerve cell death. However, the roles of c-Fos and c-Jun protein expressions in neuronal apoptosis of rats with post-ischemic reconditioning damage were not clarified. Therefore, the aim of this study was to investigate the correlations of protein expressions of c-Fos and c-Jun with neuronal apoptosis of rats with post-ischemic reconditioning damage. Rat models of post-ischemic reconditioning were established firstly. Then, apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) assay, and the gene expression levels of apoptosis-related proteins [cytochrome c (Cyt c), B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax)] were detected by reverse transcription-polymerase chain reaction (RT-PCR). Lastly, Western blotting was used to determine the protein expression levels of c-Fos and c-Jun, and the expressions of c-Fos and c-Jun in brain tissues of models were measured by immunohistochemistry. Treatment group had significantly increased malonaldehyde (MDA) level and significantly decreased superoxide dismutase (SOD) activity in rat cortex compared with those in control group (p<0.05). The number of TUNEL positive cells in the right cortex of rats in the treatment group was clearly higher than that in control group. Among them, post-ischemic reperfusion group had reduced level of Bax in the cytoplasm, but increased Bax level in the mitochondrion, and lowered expression level of Bcl-2 in both mitochondrion and cytoplasm in comparison with control group. Dynamic detection results of c-Jun were in synchronization with those of apoptosis proteins, and maximum expression occurred at 24 h after treatment. c-Jun may play a role in the initiation of apoptotic cell death in these neurons.

Neuroprotective effects of metformin on traumatic brain injury in rats associated with NF-κB and MAPK signaling pathway

Traumatic brain injury (TBI) triggers a complex sequence of inflammatory responses that contribute to secondary injury. Metformin, a first-line drug used to treat type 2 diabetes, is reported to exhibit potent anti-inflammatory activity on diseases associated with the central nervous system (CNS). The aim of this study is to investigate the potential neuroprotective effects of metformin on acute brain injury after TBI and explore the underlying mechanisms. Male Sprague-Dawley (SD) rats were divided into four groups: sham group, TBI group, TBI + saline (NS) group and TBI + metformin group. A weight-dropping model was employed to induce TBI in rats. Modified neurological severity scores (mNSS) were employed to assess the short-term neurological deficits, neuronal degeneration and apoptosis in the brain tissues were assayed with Fluoro-Jade B and TUNEL staining, immunofluorescence was designed to investigate microglial activation. The mRNA and protein expression levels of pro-inflammatory cytokines such as necrosis factor-alpha (TNF-α), interleukin-beta (IL-1β) and nterleukin-6 (IL-6) were evaluated by real-time quantitative reverse transcriptase polymerase chain reaction (QPCR) and enzyme-linked immunosorbent assay (ELISA). Western blotting analysis was engaged to examine the expression of NF-κB p65 and phosphorylation of ERK1/2 and p38 MAPK. Our results showed that metformin significantly ameliorated neurological deficit, cerebral edema and neuronal apoptosis in rats following TBI. Moreover, metformin administration inhibited microglial activation and decreased the production of pro-inflammatory cytokines including TNF-α, IL-1β and IL-6. In addition, metformin inhibited the translocation of NF-κB p65 from cytoplasm into the nucleus, as well as the phosphorylation of ERK1/2 and p38 MAPK. This study suggests that metformin administration inhibits microglia activation-mediated inflammation via NF-κB and MAPK signaling pathway to improve neurobehavioral function following TBI, which provide a potential therapeutic benefit in treating brain injury.

Retracted: Protective effects of Progranulin against focal cerebral ischemia‐reperfusion injury in rats by suppressing endoplasmic reticulum stress and NF‐κB activation in reactive astrocytes

The aim of this study is to explore the effect progranulin (PGRN) has on endoplasmic reticulum (ER) stress and the NF-κB activation in reactive astrocytes found in rat models with focal cerebral ischemia-reperfusion (I/R) injury. Sprague-Dawley (SD) rats were grouped into the sham, I/R, PGRN-high dose, PGRN-low dose, and negative control (NC) groups. TTC staining was applied in order to detect the cerebral infarction volume, a TUNEL assay to detect the apoptosis rate of neurons, an ELISA to measure MDA, SOD, iNOS, LDH, TNF-α, IL-1β, IL-6, and IL-10 levels, and both RT-qPCR and western blotting methods in order to detect PGRN, GFAP, GRP78, CHOP, and NF-κB p65 expressions. The astrocytes (AST) cells were then assigned into the normal, I/R, negative control (NC), PGRN-high dose, and PGRN-low dose groups. After completing the transfection process, the proliferative capacity of AST cells was detected by use of the CCK-8 assay. Both the in vivo and in vitro results, in comparison with the I/R and the NC groups, the PGRN-high dose and PGRN-low dose groups both presented a decrease in cerebral infarction volume, apoptosis rate of neurons, MDA, LDH, iNOS, TNF-α, IL-1β, IL-6 levels, and GFAP, GRP78, CHOP, NF-κB p65 expressions, and an increase in SOD, IL-10, and PGRN levels as well as cell proliferation depending on dosage. Based on our results, we came to the confirmation that PGRN can reduce neuronal apoptosis by mitigating ER stress in the reactive astrocytes as well as downregulating the inflammatory levels by suppressing the NF-κB signaling pathway.

Pretreatment with nimodipine reduces incidence of POCD by decreasing calcineurin mediated hippocampal neuroapoptosis in aged rats

BackgroundCalcineurin (CaN) having a high expression in hippocampal neurons is closely related to apoptosis. Pretreatment with nimodipine can lower the apoptosis rate of hippocampal neuron to reduce the incidence of postoperative cognitive dysfunction (POCD). However, the relationship between cerebral protective effect of pretreatment with nimodipine and CaN is controversial in the literature. The aim of this study is to evaluate the relationship between neuroprotective effect of nimodipine and CaN on POCD in aged rats.MethodsNinety-six 18-month-old male Sprague-Dawley rats were randomly assigned into 4 groups (n = 24 each): control group (Group C), nimodipine group (Group N), surgery group (Group S) and nimodipine + surgery group (Group N + S). In Group N and Group N + S, nimodipine 1 mg/kg was intraperitoneally injected, while the equal volume of normal saline was given instead in Group S. 30 min later, Group N and Group C inhaled pure oxygen for 2 h, and Group S and N + S inhaled 3% sevoflurane for 2 h when exploratory laparotomy was performed. Morris water maze test was performed on 1 day before operation and 1, 3 and 7 days after operation. After the end of Morris water maze test at 1 day before operation and 1 and 7 days after operation, 8 rats were sacrificed, brains were removed and hippocampal tissues were obtained for detection of apoptosis in hippocampal neurons, cytoplasmic calcium ([Ca2+]i), and hippocampal CaN and caspase-3 expression.ResultsCompared with the 1st day before operation, the escape latency, apoptosis rate, [Ca2+]i, expression of CaN and caspase-3 increased significantly, but the frequency of crossing the original platform decreased dramatically in Group S and N + S(P<0.05). In addition, the escape latency, apoptosis rate, [Ca2+]i, and expression of CaN and caspase-3 decreased markedly, but the frequency of crossing the original platform increased significantly in Group N + S as compared with Group S (P<0.05).ConclusionsPretreatment with nimodipine reduces the incidence of POCD by decreasing CaN mediated hippocampal neuroapoptosis in aged rats.

The protective effects of distal ischemic treatment on apoptosis and mitochondrial permeability in the hippocampus after cardiopulmonary resuscitation.

Apoptosis and mitochondrial dysfunction are the main cause of neurological injury after cardiopulmonary resuscitation (CPR). However, the effects of distal ischemic treatments on ischemia induced apoptosis are rarely studied, and the mechanism by which mitochondrial dysfunction contributes to CPR still unclear. A rat model of distal ischemia was established by clipping the right femoral artery. Rats were divided into blank, model, pre distal ischemic treatment, per-treatment, and post-treatment groups. Neurological deficit score was scored to evaluate neurologic function after cardiopulmonary resuscitation for 72 hr. We employed TUNEL and flow cytometry to measure the rate of apoptosis of hippocampal neurons, the integrity of mitochondrial membrane and the degree of mitochondrial permeability transition pore (mPTP) opening. The rate of apoptosis rate of hippocampal CA1 neurons in the pre-treatment and post-treatment groups were significantly lower than that of the model group. Moreover, the integrity of the mitochondrial membrane in the pre-treatment and post-treatment groups was higher than that in the model and per- treatment groups. Furthermore, the degree of mPTP opening was lower in the pre-treatment and post-treatment groups than the untreated and per-treatment groups. Taken together, our results show that ischemic preconditioning and post processing can maintain the integrity of mitochondria, perhaps by inhibiting the opening of mPTP, and reducing apoptosis of hippocampal neurons by regulating expression of apoptosis related proteins after CPR, to improve neurological function. This study highlights a novel target pathway for treatment of CPR.

Neuroprotective effects of salidroside administration in a mouse model of Alzheimer's disease.

Salidroside administration improves memory in different models of learning. However, its influence on models of Alzheimer's disease (AD) has not been widely studied. In the present study, the therapeutic effect of salidroside was investigated in an animal model of AD. APPswe/PS1ΔE9 mouse (n=20) were randomly divided into either the AD model group or the salidroside+AD model group (n=10 in each group), and C57BL/6J mouse (n=20) of identical age and genetic background were randomly divided into either the normal control (NC) group or the salidroside+NC group (n=10 in each group). The Morris water maze behavioral test was applied to all mice in order to investigate the effects of salidroside administration on learning and memory functions. The concentrations of malondialdehyde (MDA), glutathione(GSH) and nitrate in the hippocampus of the mice were determined, and hippocampal superoxide dismutase (SOD) activity was also determined. In addition, terminal deoxynucleotidyl‑transferase‑mediated dUTP nick end labeling was used to investigate the rate of neuronal apoptosis in the hippocampus. Furthermore, the concentrations of interleukin‑6 (IL‑6) and tumor necrosis factor‑α (TNF‑α) were tested for in the brain tissues of AD mice. Learning and memory functions in AD mice were revealed to improve following administration of salidroside. Furthermore, salidroside administration was revealed to decrease the concentrations of MDA and nitrate in the hippocampus, decrease the apoptotic rate of hippocampal neurons, and increase the activity of SOD and the concentration of GSH in hippocampal tissue. In addition, it was demonstrated that salidroside administration suppressed the expression levels of IL‑6 and TNF‑α. In conclusion, this study revealed that the administration of salidroside could attenuate the effects of AD‑associated memory and learning impairment in mice. Furthermore, it was demonstrated that the effects of salidroside administration on AD mice were, at least partially, via inhibition of brain oxidative/nitrosative damage, suppression of both IL‑6 and TNF‑α expression levels, and suppression of the hippocampal neuronal apoptotic rate.

MicroRNA-140-5p elevates cerebral protection of dexmedetomidine against hypoxic-ischaemic brain damage via the Wnt/β-catenin signalling pathway.

Hypoxia–ischaemia (HI) remains a major cause of foetal brain damage presented a scarcity of effective therapeutic approaches. Dexmedetomidine (DEX) and microRNA‐140‐5p (miR‐140‐5p) have been highlighted due to its potentially significant role in the treatment of cerebral ischaemia. This study was to investigate the role by which miR‐140‐5p provides cerebral protection using DEX to treat hypoxic–ischaemic brain damage (HIBD) in neonatal rats via the Wnt/β‐catenin signalling pathway. The HIBD rat models were established and allocated into various groups with different treatment plans, and eight SD rats into sham group. The learning and memory ability of the rats was assessed. Apoptosis and pathological changes in the hippocampus CA1 region and expressions of the related genes of the Wnt/β‐catenin signalling pathway as well as the genes responsible of apoptosis were detected. Compared with the sham group, the parameters of weight, length growth, weight ratio between hemispheres, the rate of reaching standard, as well as Bcl‐2 expressions, were all increased. Furthermore, observations of increased levels of cerebral infarction volume, total mortality rate, response times, total response duration, expressions of Wnt1, β‐catenin, TCF‐4, E‐cadherin, apoptosis rate of neurons, and Bax expression were elevated. Following DEX treatment, the symptoms exhibited by HIBD rats were ameliorated. miR‐140‐5p and si‐Wnt1 were noted to attenuate the progression of HIBD. Our study demonstrates that miR‐140‐5p promotes the cerebral protective effects of DEX against HIBD in neonatal rats by targeting the Wnt1 gene through via the negative regulation of the Wnt/β‐catenin signalling pathway.

The protective effect of hypoxia preconditioning on epilepsy induced by lithium-pilocarpine in rats

Objective To investigate the brain protection of intermittent hypoxia preconditioning (IHP) on rats with seizures induced by lithium-pilocarpine (Li-pilo). Methods 96 rats were randomly divided into control group, seizure group and four IHP-seizure group. The animal model of epilepsy was established by Li-pilo intraperitoneal injection in seizure group and four IHP-seizure groups (Li-pilo was injected 1, 3, 7, or 14 days after a 5-day regimen of IHP). Subsequently, 240 min video data of seizure behavior was tested, histological grade (HG) and neuronal density (ND) in rat hippocampal CA1 subfield via terminal deoxynucleotidyl transferase mediated dUTP biotin nick end labeling (TUNEL) and Nissl’s staining. Results Modified Racine scales of induced seizure peaked on average between 50-150 min after Li-pilo administration. The average peak score in IHP-3 d seizure group [(1.42±0.50) points, P=0.007] was significantly lower than seizure group [(4.15±0.72) points] and IHP-1 d [(2.16±0.69) points, P=0.028]; 7 d [(2.26±0.53) points, P=0.030] seizure group. The average escape latency in seizure rats [(54.33±3.90) s was significantly longer than Control group [(36.95±15.71) s, P=0.011], IHP-1 d seizure group [(44.83±11.68) s, P=0.047], IHP-3 d seizure group [(38.75±15.32) s, P=0.012] and IHP-7 d seizure group [(44.73±11.18) s, P=0.045]. The neuronal apoptosis rate and HG in seizure group were also higher than the other groups. The average percentage of time in the probe quadrant and ND value in seizure rats [(29.63±4.95)%; (35.25±8.37) cells/HP] were obviously lower than Control group [(41.13±19.09)%, P=0.013; (110.35±9.87) cells/HP, P=0.000], IHP-1 d seizure group [(36.13±13.97)%, P=0.037; (65.31±7.25) cells/HP, P=0.007], IHP-3 d seizure group [(42.38±20.15)%, P=0.011; (98.50±14.20) cells/HP, P=0.000] and IHP-7 d seizure group [(33.94±8.75)%, P=0.040; (54.80±11.68) cells/HP, P=0.010]. Conclusion The results indicate that 5-day IHP manipulation can afford definite anti-epileptic functions to epileptic model rats. Key words: Hypoxia preconditioning; Epilepsy; Apoptosis; Neuroprotection; Rat

Local Delivery of β-Elemene Improves Locomotor Functional Recovery by Alleviating Endoplasmic Reticulum Stress and Reducing Neuronal Apoptosis in Rats with Spinal Cord Injury

Background/Aims: Spinal cord injury (SCI) is a serious global problem that leads to permanent motor and sensory deficits. This study explores the anti-apoptotic and neuroprotective effects of the natural extract β-elemene in vitro and in a rat model of SCI. Methods: CCK-8 assay was used to evaluate cell viability and lactate dehydrogenase assay was used to evaluate cytotoxicity. A model of cell injury was established using cobalt chloride. Apoptosis was evaluated using a fluorescence-activated cell sorting assay of annexin V-FITC and propidium iodide staining. A rat SCI model was created via the modified Allen’s method and Basso, Beattie, and Bresnahan (BBB) scores were used to assess locomotor function. Inflammatory responses were assessed via enzyme-linked immunosorbent assay (ELISA). Apoptotic and surviving neurons in the ventral horn were respectively observed via terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and Nissl staining. Western blotting was used to measure protein expression. Results: β-elemene (20 μg/ml) promoted cell viability by activating phosphorylation of the PI3K-AKT-mTOR pathway. β-elemene reduced CoCl₂-induced cellular death and apoptosis by suppressing the expression levels of CHOP, cleaved-caspase 12, 78-kilodalton glucose-regulated protein, cleaved-caspase 3, and the Bax/Bcl-2 ratio. In the rat model of SCI, Nissl and TUNEL staining showed that β-elemene promoted motor neuron survival and reduced neuronal apoptosis in the spinal cord ventral horn. BBB scores showed that β-elemene significantly promoted locomotor behavioral recovery after SCI. In addition, β-elemene reduced the ELISA-detected secretion of interleukin (IL)-6 and IL-1β. Conclusion: β-elemene reduces neuronal apoptosis by alleviating endoplasmic reticulum stress in vitro and in vivo. In addition, β-elemene promotes locomotor function recovery and tissue repair in SCI rats. Thus, our study provides a novel encouraging strategy for the potential treatment of β-elemene in SCI patients.

Affect of sevofluranein on the developmental hippocampal neurons of rats and its possible mechanism

Objective: To study the effect of sevofluranein on the developmental hippocampal neurons of rats and the possible mechanism. Methods: Hippocampal neurons were harvested from within 24 h-old Sprague-Dawley rats and cultured in the different media. Then Hippocampal neurons were randomly divided into 4 groups and treated with air (control group, CG), sevofluranein (1 minimum alveolar concentration) for 3 h (S3 group), 6 h (S6 group), 12 h (S12 group) respectively. Average neurite length and mean optical density (MOD) were used as statistical indexed and detected. Proliferation was quantified by flow cytometry. BDNF and TrkB protein expression were assessed by Western blot. Results: Average neurite length and MOD showed the same result between S3 group and CG (P>0.05), while the opposite result appeared in S6 group and S12 group (P<0.05). S6 group decreased with significant difference compared with S3 group and S12 group (P<0.05). Compared with CG and S3 group, neuronal apoptosis rate in S6 group and S12 group increased (P<0.05). BDNF and TrkB protein expression in S6 group and S12 group was lower than those in CG, while that in S3 group was higher (P<0.05) and gray value had the same result. Conclusion: The effect of sevoflurane on hippocampal neurons in vitro is bidirectional which may be related to the time through the BDNF-TrkB pathway.