Cucurbitacin B Exerts Significant Antidepressant-Like Effects in a Chronic Unpredictable Mild Stress Model of Depression: Involvement of the Hippocampal BDNF-TrkB System.

BACKGROUND: Although depression has been a serious neuropsychiatric disorder worldwide, current antidepressants used in clinical practice have various weaknesses, including delayed onset and low rates of efficacy. Recently, the development of new antidepressants from natural herbal medicine has become one of the important research hotspots. Cucurbitacin B is a natural compound widely distributed in the Cucurbitaceae and Cruciferae families and has many pharmacological activities. The present study aimed to investigate whether cucurbitacin B possess antidepressant-like effects in mice. METHODS: The antidepressant-like effects of cucurbitacin B on mice behaviors were explored using the forced swim test, tail suspension test, open field test, sucrose preference test, and a chronic unpredictable mild stress model of depression together. Then, western blotting and immunofluorescence were used to examine the effects of cucurbitacin B on the brain-derived neurotrophic factor (BDNF)-tyrosine kinase B (TrkB) signaling cascade and neurogenesis in the hippocampus of mice. Furthermore, BDNF-short hairpin RNA, K252a, and p-chlorophenylalanine methyl ester were adopted together to determine the antidepressant mechanism of cucurbitacin B. RESULTS: It was found that administration of cucurbitacin B indeed produced notable antidepressant-like effects in mice, which were accompanied with significant promotion in both the hippocampal BDNF-TrkB pathway and neurogenesis. The antidepressant mechanism of cucurbitacin B involves the hippocampal BDNF-TrkB system but not the serotonin system. CONCLUSIONS: Cucurbitacin B has the potential to be a novel antidepressant candidate.

Effect of melatonin on regeneration of cortical neurons in rats with traumatic brain injury.

PURPOSE: To investigate the effect of melatonin on regeneration of cortical neurons in rats with traumatic brain injury (TBI). METHODS: Sprague-Dawley rats (n=36) were randomly divided into sham, TBI+vehicle and TBI+melatonin groups. Cerebral blood flow and cognitive function were observed via laser Doppler flowmetry and by Morris water maze testing, respectively. The serum malondialdehyde (MDA) and superoxide dismutase (SOD) levels were used to assess oxidative stress. Immunofluorescence and terminal deoxynucleotidyl transferase dUTP nick end labelling assay was used to observe the newborn neurons and apoptotic cells. RESULTS: Cerebral blood flow in the TBI+melatonin group was higher than that of the TBI+vehicle group at one, 12, 24 and 48 h post-injury, but the difference was not statistically significant (P>0.05). The cognitive function of the rats was better in the TBI+melatonin group than the TBI+vehicle group (P.

Expression of Dixdc1 and its Role in Astrocyte Proliferation after Traumatic Brain Injury.

DIX domain containing 1 (Dixdc1), a positive regulator of Wnt signaling pathway, is recently reported to play a role in the neurogenesis. However, the distribution and function of Dixdc1 in the central nervous system (CNS) after brain injury are still unclear. We used an acute traumatic brain injury (TBI) model in adult rats to investigate whether Dixdc1 is involved in CNS injury and repair. Western blot analysis and immunohistochemistry showed a time-dependent up-regulation of Dixdc1 expression in ipsilateral cortex after TBI. Double immunofluorescent staining indicated a colocalization of Dixdc1 with astrocytes and neurons. Moreover, we detected a colocalization of Ki-67, a cell proliferation marker with GFAP and Dixdc1 after TBI. In primary cultured astrocytes stimulated with lipopolysaccharide, we found enhanced expression of Dixdc1 in parallel with up-regulation of Ki-67 and cyclin A, another cell proliferation marker. In addition, knockdown of Dixdc1 expression in primary astrocytes with Dixdc1-specific siRNA transfection induced G0/G1 arrest of cell cycle and significantly decreased cell proliferation. In conclusion, all these data suggest that up-regulation of Dixdc1 protein expression is potentially involved in astrocyte proliferation after traumatic brain injury in the rat.

Up-regulation of Vps4A promotes neuronal apoptosis after intracerebral hemorrhage in adult rats.

Vps4, vacuolar protein sorting 4, belongs to ATPases Associated with diverse cellular Activities (AAA) protein family which is made up of Vps4A and Vps4B. Previous studies demonstrated that Vps4A plays vital roles in diverse aspects such as virus budding, the efficient transport of H-Ras to the PM (plasma membrane) and the involvement in the MVB (multivesiculate bodies) pathway. Interestingly, Vps4A is also expressed in the brain. However, the distribution and function of Vps4A in ICH diseases remain unclear. In this study, we show that Vps4A may be involved in neuronal apoptosis during pathophysiological processes of intracerebral hemorrhage (ICH). Based on the results of Western blot and immunohistochemistry, we found a remarkable up-regulation of Vps4A expression surrounding the hematoma after ICH. Double labeled immunofluorescence showed that Vps4A was co-expressed with NeuN but rarely with astrocytes and microglia. Morever, we detected that neuronal apoptosis marker active caspase-3 had co-localizations with Vps4A. Additionaly, Vps4A knockdown in vitro specifically leads to decreasing neuronal apoptosis coupled with increased Akt phosphorylation. All datas suggested that Vps4A was involved in promoting neuronal apoptosis via inhibiting Akt phosphorylation after ICH.

[Protective effects of LBP on cerebral ischemia reperfusion injury in mice and mechanism of inhibiting NF-κB, TNF-α, IL-6 and IL-1ß].

To observe the protective effects of Lycium barbarum polysaccharides (LBP) on cerebral ischemia reperfusion injury in mice and explore its mechanism. Common carotid artery thread was used to cause middle cerebral artery ischemia, and the thread was taken out after 2 h ischemia to achieve cerebral ischemia reperfusion injury in mice. Therefore, the transient middle cerebral artery occlusion (tMCAO) models were established to observe the effects of LBP (25,50, 100 mg•kg⁻¹) on neurological outcome, infarct size and water contents. HE staining was used to observe its effects on neurocytes of cerebral tissues in mice. Western blotting was used to evaluate the protein expression levels of NF-κB p65. ELISA was used to evaluate the levels of TNF-α, IL-6 and IL-1ß in the serum. According to the results, LBP markedly improved neurologic deficits, and decreased infarct size and water contents at 24 h after reperfusion in mice. Pathological section of brain tissues also proved its protective effects on neurocytes. Western blot analysis indicated that LBP markedly down-regulated the protein level of NF-κB p65. ELISA indicated that LBP decreased the levels of TNF-α, IL-6 and IL-1ß in the serum 24 h after reperfusion.In conclusion, LBP has protective effects on cerebral ischemia reperfusion injury in mice, and this effect may be associated with inhibiting NF-κB and inflammatory reactions.

Up-Regulation of Interferon Regulatory Factor 3 Involves in Neuronal Apoptosis After Intracerebral Hemorrhage in Adult Rats.

Interferon regulatory factor 3 (IRF3) is a member of IRF family which plays a significant role in the innate immune response, apoptosis, and oncogenesis. Mounting evidence has demonstrated that IRF3 was involved in central nervous system disease such as cerebral ischemic injury through promoting neuronal apoptosis. However, it remains unclear about the underlying mechanisms of IRF3 upon neuronal apoptosis following intracerebral hemorrhage (ICH). In the present study, we established an adult rat ICH model by injecting autologous whole blood into the right basal ganglia and evaluated their neurological deficits by behavioral tests. IRF3 protein level was up-regulated adjacent to the hematoma following ICH when compared with the sham brain cortex by western blot and immunohistochemistry. Immunofluorescent staining indicated IRF3 was mainly localized in neurons, a few in astrocytes. In addition, we also detected that IRF3 co-localized with active caspase-3 which is a neuronal apoptosis marker. Furthermore, in vitro study, knocking down IRF3 by using IRF3 interference in primary cortical neurons reduced the expression of active caspase-3 and Bax while increased Bcl-2. In conclusion, we speculated that IRF3 might exert pro-apoptotic function in neurons after ICH.

Particulate Matter Facilitates C6 Glioma Cells Activation and the Release of Inflammatory Factors Through MAPK and JAK2/STAT3 Pathways.

It has been widely accepted that astrocytes, play a role in regulating almost every physiological system. In the present study, we investigated the role of particulate matter (PM) in regulating activation of astrocytes. The glial cell strain C6 was cloned from a rat glioma which was induced by N-nitrosomethylurea. The C6 cells were plated at a density of 5 × 10(6) cells/10 cm diameter dish and incubated with different concentrations (0, 12, 25, 50, 100, 200, and 400 µg/mL) of PM for 24 h and different time (0, 1, 3, 6, 8,12, and 24 h) with 100 µg/mL at 37 °C. The study revealed that PM stimulated the expression of inducible nitric oxide synthase (iNOS) as well as the production of IL-1ß in a dose- and time-dependent manner. Furthermore, activation of JAK2/STAT3 and p38/JNK/ERK MAPKs was found in astrocytes following PM treatment. Blockage of JAK and p38/JNK/ERK MAPKs with their specific inhibitors, AG490, SB202190, SP600125 and U0126 significantly reduced PM-induced iNOS expression and IL-1ß production. In addition, it was demonstrated that inhibition of p38, JNK and JAK prevented STAT3 tyrosine phosphorylation induced by PM, while blocking ERK did not. MAPKs (p38 and JNK) could regulate tyrosine STAT3 phosphorylation, which suggested that the JAK2/STAT3 pathway might be the downstream of p38/JNK MAPK pathways.

A TIGAR-regulated metabolic pathway is critical for protection of brain ischemia.

TP53-induced glycolysis and apoptosis regulator (TIGAR) inhibits glycolysis and increases the flow of pentose phosphate pathway (PPP), which generates NADPH and pentose. We hypothesized that TIGAR plays a neuroprotective role in brain ischemia as neurons do not rely on glycolysis but are vulnerable to oxidative stress. We found that TIGAR was highly expressed in brain neurons and was rapidly upregulated in response to ischemia/reperfusion insult in a TP53-independent manner. Overexpression of TIGAR in normal mice with lentivirus reduced ischemic neuronal injury, whereas lentivirus-mediated TIGAR knockdown aggravated it. In cultured primary neurons, increasing TIGAR expression reduced oxygen and glucose deprivation (OGD)/reoxygenation-induced injury, whereas decreasing its expression worsened the injury. The glucose 6-phosphate dehydrogenase was upregulated in mouse and cellular models of stroke, and its upregulation was further enhanced by overexpression of TIGAR. Supplementation of NADPH also reduced ischemia/reperfusion brain injury and alleviated TIGAR knockdown-induced aggravation of ischemic injury. In animal and cellular stroke models, ischemia/reperfusion increased mitochondrial localization of TIGAR. OGD/reoxygenation-induced elevation of ROS, reduction of GSH, dysfunction of mitochondria, and activation of caspase-3 were rescued by overexpression of TIGAR or supplementation of NADPH, while knockdown of TIGAR aggravated these changes. Together, our results show that TIGAR protects ischemic brain injury via enhancing PPP flux and preserving mitochondria function, and thus may be a valuable therapeutic target for ischemic brain injury.

Protective Effect of Pyrroloquinoline Quinone (PQQ) in Rat Model of Intracerebral Hemorrhage.

Pyrroloquinoline quinone (PQQ) has invoked considerable interest because of its presence in foods, antioxidant properties, cofactor of dehydrogenase, and amine oxidase. Protective roles of PQQ in central nervous system diseases, such as experimental stroke and spinal cord injury models have been emerged. However, it is unclear whether intracerebral hemorrhage (ICH), as an acute devastating disease, can also benefit from PQQ in experimental conditions. Herein, we examined the possible effect of PQQ on neuronal functions following ICH in the adult rats. The results showed that rats pretreated with PQQ at 10 mg/kg effectively improved the locomotor functions, alleviated the hematoma volumes, and reduced the expansion of brain edema after ICH. Also, pretreated rats with PQQ obviously reduced the production of reactive oxygen species after ICH, probably due to its antioxidant properties. Further, we found that, Bcl-2/Bax, the important indicator of oxidative stress insult in mitochondria after ICH, exhibited increasing ratio in PQQ-pretreated groups. Moreover, activated caspase-3, the apoptotic executor, showed coincident alleviation in PQQ groups after ICH. Collectively, we speculated that PQQ might be an effective and potential neuroprotectant in clinical therapy for ICH.

TP53-induced glycolysis and apoptosis regulator (TIGAR) ameliorates lysosomal damage in the 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine-mediated mouse model of Parkinson's disease.

The progressive loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) correlates with rupture of lysosome in Parkinson's disease (PD). It has been found that TP53-induced glycolysis and apoptosis regulator (TIGAR) has been attributed to the regulation of metabolic pathways and neuroprotective effect. In the present study, we showed in a mouse model that 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) caused lysosomal damage and DA neurons loss in the SNpc. MPTP only induced SP1-mediated TIGAR upregulation in the early stage of neurotoxin-induced pathology, and this compensatory mechanism was not enough to maintain normal lysosomal function. MPTP significantly decreased the levels of NADPH and GSH, and the effects were ameliorated by the expression of exogenous TIGAR but execerbated by knockdown of TIAGR. TIGAR or NADPH alleviated oxidative stress, rescued lysosomal dysfunction and attenuated DA neurons degeneration. Overexpression of TIGAR or NADPH supplement inhibited MPP+-mediated reactive oxygen species (ROS), lysosomal membrane permeabilization (LMP) and autophagic flux impairment in PC12 cells. Together, these findings suggest that TIGAR reduces MPTP-mediated oxidative stress, lysosomal depletion and DA neuron damage.

[Effect of tranexamic acid combined flexion position of hip and knee on perioperative bleeding following unilateral total knee arthroplasty].

OBJECTIVE: To explore clinical efficacy and safety of application of tranexamic acid for two times combined with postoperative hip and knee on flexion position for reducing blood loss during total knee arthroplasty. METHODS: From January 2015 to January 2018, 90 patients with knee osteoarthritis underwent unilateral total knee arthroplasty, including 33 males and 57 females, aged from 61 to 85 years old with an average of(72.3±6.9) years old. The patients were randomly divided into three groups according to random number table, 30 patients in each group. In group A, there were 11 males and 9 females, aged from 61 to 84 years old with an average of (71.60±6.04) years old, body mass index was (26.04±1.95) kg/m², hemoglobin was(128.57±5.98) g/L, treated by 7.5 mg/kg tranexamic acid was injected intravenously before upper tourniquet, and 7.5 mg/kg tranexamic acid after closure of incision and before loosening tourniquet, meanwhile combined with flexion position of hip for 30° to 45° and flexion position of knee for 60° for 70°. In group B, there were 10 males and 20 females aged from 61 to 85 years old with an average of (72.04±7.47) years, body mass index was (25.92±1.70) kg/m², hemoglobin was (127.58±4.37) g/L, treated by 15 mg/kg tranexamic acid injected intravenously before loosening tourniquet. In group C, there were 12 males and 18 females aged from 62 to 85 years old with an average of (73.23±7.36) years, body mass index was (26.07±1.49) kg/m², hemoglobin was (128.31±5.61) g/L, treated with the same amount of normal saline before loosening tourniquet. Intraoperative bleeding volume, postoperative drainage volume, recessive blood loss, total blood loss volume, blood transfusion cases, activated partial thromboplastin time(APTT), prothrombin time(PT), prothrombin international standardized ratio (PT-INR) and indexes of D-dimer(D-D) were compared among three groups, as well as postoperative deep venous thrombosis and pulmonary embolism were observed among three groups. RESULTS: No incision infection occurred in all 90 patients, and all patients were followed up from 4 to 8 months with an average of 6 months without pulmonary embolism occurred. There was no statistical difference in itraoperative bleeding volume among three groups(F=0.299, P=0.742), while there were significant differences in postoperative drainage volume, recessive blood loss, and total blood loss among three groups. The number of blood transfusion were as following, 2 cases in group A, 8 cases in group B, and 16 cases in group C, there were statistically significant differences among three groups(χ² =16.01, P<0.001). There were no differences in APTT, PT, PT-INR and D-D after operation among three groups(P>0.05), and no difference in occurrence of lower limb vein thrombosis after operation. CONCLUSIONS: The method of using tranexamic acid before upper tourniquet, after closure of incision and before loosening tourniquet-combined with the flexion position of hip and knee could effectively reduce postoperative drainage volume, recessive bleeding, total blood loss and blood transfusion cases after total knee arthroplasty, while it does not increase risk of deep vein thrombosis and pulmonary embolism.

O-GlcNAcylation Reduces Ischemia-Reperfusion-Induced Brain Injury.

O-GlcNAcylation is a common posttranslational modification of nucleocytoplasmic proteins with ß-N-acetylglucosamine (GlcNAc) and regulates numerous biological processes. By using mouse models of cerebral ischemia induced by permanent and transient middle cerebral artery occlusion (MCAO), we observed an initial elevation (~1.7-fold, 1-4 hours after ischemia) and then decline of O-GlcNAcylation during cerebral ischemia. We found that moderate increase (<3-fold) of brain O-GlcNAcylation by pharmacological means ameliorated cerebral ischemia-reperfusion injury and the consequent motor and neurological deficits. Interference of the transient elevation of O-GlcNAcylation pharmacologically or genetically aggravates the ischemia-induced brain damage, motor deficits and mortality. The alteration of O-GlcNAcylation was also seen in the ischemic areas of postmortem human brains. This study reveals an important regulation of cerebral ischemia-reperfusion injury by O-GlcNAcylation and also provides a possible therapeutic strategy, i.e., by increasing O-GlcNAcylation, to reduce the cerebral damage and improve the clinical outcome of ischemic stroke.

ROS-mediated apoptosis of HAPI microglia through p53 signaling following PFOS exposure.

Perfluorooctane sulfonate (PFOS), the most extensively studied member of perfluoroalkyl and polyfluoroalkyl substances (PFASs), has been thought to be toxic to the central nervous system (CNS) of mammals. However, the neurotoxic effects of PFOS remain largely unknown. In this study, the effect of PFOS on microglial apoptosis was examined. The results showed that PFOS could significantly reduce the cell viability and mediate cell apoptosis in HAPI microglia, which was closely accompanied with ROS production and p53 overexpression. Moreover, p53 interference significantly ameliorated PFOS-triggered cytotoxic effects in HAPI microglia, including the downregulation of cleaved PARP and cleaved caspase 3. Interestingly, NAC, a ROS inhibitor, inhibited p53 expression, and decreased the apoptosis of HAPI microglia. Taken together, these findings suggest that upregulated production of ROS plays a vital role in PFOS-mediated apoptosis in HAPI microglia via the modulation of p53 signaling.

Up-regulation of PSMB4 is associated with neuronal apoptosis after neuroinflammation induced by lipopolysaccharide.

Proteasomes are major intracellular extralysosomal organelle for protein degradation and a central source of antigenic peptides in the endogenous pathway. Proteasome beta-4 subunit (PSMB4) was recently identified as potential cancer driver genes in several tumors. However, information regarding its regulation and possible function in the central nervous system is still limited. The present study was designed to elucidate dynamic changes in PSMB4 expression and distribution in the cerebral cortex in a lipopolysaccharide (LPS)-induced neuroinflammation rat model. It was found that PSMB4 expression was increased significantly in apoptotic neurons in the brain cortex after LPS injection. Moreover, there was a concomitant up-regulation of active caspase-3, cyclin D1, and CDK4 in vivo and vitro studies. In addition, these three proteins in cortical primary neurons were decreased after knocking down PSMB4 by siRNA. Collectively, these results suggested that PSMB4 may be involved in neuronal apoptosis in neuroinflammation after LPS injection.

Ginkgolide B prevents cathepsin-mediated cell death following cerebral ischemia/reperfusion injury.

Ginkgolide B (GB) has been shown to exert neuroprotective effects against cerebral ischemia/reperfusion (I/R) injury. However, the underlying mechanism by which GB prevents ischemic cell death remains unclear. Lysosomal proteases, including cathepsins B and L, have been implicated in ischemic cell death following reperfusion. Therefore, in the present study, we investigated the role of GB with respect to cathepsin-mediated cell death following I/R. Both the expression and enzymatic activity of cathepsins B and L were significantly increased in the ischemic cortex following cerebral I/R injury. We found that GB treatment markedly decreased the activity and expression of cathepsins B and L following I/R. Moreover, GB reduced necrotic and apoptotic cell death following I/R. These data strongly suggest that GB prevents cathepsin-mediated cell death following focal cerebral I/R injury, and they might provide new insights into the mechanism of the neuroprotective effects of GB.

The pro-survival role of autophagy depends on Bcl-2 under nutrition stress conditions.

Autophagy can be induced under nutrition stress conditions. Bcl-2 is a pro-survival protein which inhibits apoptosis and autophagy. However, the role of Bcl-2 in autophagy regulation and cell survival under nutrition deprivation has not been fully understood. This study sought to investigate if Bcl-2 upregulation is essential in limiting autophagic activity and prevent cell death under nutrition deprivation conditions. Autophagic activity was monitored by the changes in GFP-LC3 localization and protein levels of Beclin1, LC3-II, cathepsin D and p62 in neuroblastoma SH-SY5Y cells underwent serum deprivation. Manipulation of Bcl-2 function was achieved with siRNAs and small molecular inhibitors. The cell viability and apoptosis were assessed with MTT assay and Annexin V/PI staining. The results showed that serum starvation increased protein levels of LC3-II and Beclin1 but decreased autophagy substrate p62. Autophagy activation induced by serum deprivation and rapamycin was accompanied by an upregulation of Bcl-2 protein levels. When Bcl-2 was knocked down with siRNA or inhibited with HA 14-1 or ABT-737, serum starvation induced profound cell death and enhanced autophagic flux under nutrition deprivation conditions, while knockdown of autophagic gene Beclin1 or autophagy inhibitors (bafilomycin A1 and E64D), rescued cell death. In contrast, overexpression of Bcl-2 inhibited autophagy and blocked cell death in response to serum deprivation. These data suggest that Bcl-2 plays an essential role in limiting autophagy activation and preventing initiation of programmed cell death. Thus Bcl-2 may be an important mechanism for balancing beneficial and detrimental impacts of autophagy on cell survival.

Poloxamer 188 protects neurons against ischemia/reperfusion injury through preserving integrity of cell membranes and blood brain barrier.

Poloxamer 188 (P188), a multiblock copolymer surfactant, has been shown to protect against ischemic tissue injury of cardiac muscle, testes and skeletal muscle, but the mechanisms have not been fully understood. In this study, we explored whether P188 had a protective effect against cerebral ischemia/reperfusion injury and its underlying mechanisms. The in vivo results showed that P188 significantly reduced the infarct volume, ameliorated the brain edema and neurological symptoms 24 h after ischemia/reperfusion. In the long-term outcome study, P188 markedly alleviated brain atrophy and motor impairments and increased survival rate in 3 weeks of post stroke period. Additionally, P188 protected cultured hippucampal HT22 cells against oxygen-glucose deprivation and reoxygenation (OGD/R) injury. The ability in membrane sealing was assessed with two fluorescent membrane-impermeant dyes. The results showed that P188 treatment significantly reduced the PI-positive cells following ischemia/reperfusion injury and repaired the HT22 cell membrane rupture induced by Triton X-100. In addition, P188 inhibited ischemia/reperfusion-induced activation of matrix metalloproteinase (MMP)-9 and leakage of Evans blue. Therefore, the present study concludes that P188 can protect against cerebral ischemia/reperfusion injury, and the protection involves multi-mechanisms in addition to the membrane resealing.

p38(MAPK)/p53-Mediated Bax induction contributes to neurons degeneration in rotenone-induced cellular and rat models of Parkinson's disease.

Rotenone is an environmental neurotoxin that induces degeneration of dopaminergic (DA) neurons in substantia nigra pars compacta (SNpc), which ultimately results in parkinsonism, but the molecular mechanisms of selective degeneration of nigral DA neurons are not fully understood. In the present study, we investigated the induction of p38(MAPK)/p53 and Bax in SNpc of Lewis rats after chronic treatment with rotenone and the contribution of Bax to rotenone-induced apoptotic commitment of differentiated PC12 cells. Lewis rats were subcutaneously treated with rotenone (1.5mg/kg) twice a day for 50days and the loss of tyrosine hydroxylase (THase), motor function impairment, and expression of p38(MAPK), P-p38(MAPK), p53, and Bax were assessed. After differentiated PC cells were treated with rotenone (500nM) for 6-36h, protein levels of p38(MAPK) and P-p38(MAPK), p53 nuclear translocation, Bax induction and cell death were measured. The results showed that rotenone administration significantly reduced motor activity and caused a loss of THase immunoreactivity in SNpc of Lewis rats. The degeneration of nigral DA neurons was accompanied by the increases in p38(MAPK), P-p38(MAPK), p53, and Bax protein levels. In cultured PC12 cells, rotenone also induced an upregulation of p38(MAPK), P-p38(MAPK), p53 and Bax. Pharmacological inhibition of p38(MAPK) with SB203580 (25µM) blunted rotenone-induced cell apoptosis. Treatment with SB203580 prevented the p53 nuclear translocation and upregulation of Bax. Inhibition of p53 with pifthrin-alpha or Bax with siRNAs significantly reduced rotenone-induced Bax induction and apoptotic cell death. These results suggest that the p38(MAPK)/p53-dependent induction of Bax contributes to rotenone's neurotoxicity in PD models.

Inhibition of NF-κB activation is associated with anti-inflammatory and anti-apoptotic effects of Ginkgolide B in a mouse model of cerebral ischemia/reperfusion injury.

Ginkgolide B (GB) has potent neuroprotective effects against ischemia-induced brain injury in vivo and in vitro. However, the underlying mechanisms of GB's neuroprotection remain poorly understood. Excessive inflammation and apoptosis contribute to the pathogenesis of ischemic brain damage, and NF-κB is considered to be a key player in these processes. In the present study, we examined the detailed mechanisms underlying the inhibitory effects of GB on inflammatory and apoptotic responses induced by focal cerebral ischemia/reperfusion (I/R). Transient middle cerebral artery occlusion (tMCAO) model was produced by using an intraluminal filament technique in mice. GB (10, 20 and 40 mg/kg) was administered intravenously (i.v.) 2h after MCAO. The results demonstrated that MCAO-induced cerebral injury was associated with an upregulation of p-IKK, p-IκB-α and degradation of IκB-α, indicating of NF-κB activation. Meanwhile activation of microglial and increases in levels of TNF-α, IL-1ß and iNOS were observed. Furthermore upregulation of the expression of NF-κB target gene p53 and p53 downstream gene Bax, but downregulation of Bcl-2 and activation of caspase-3 were found. GB treatment showed marked reduction in infarction volume, brain edema and neurological deficits. GB also inhibited I/R induced NF-κB, microglia activation and production of pro-inflammatory cytokines. We also demonstrated that GB reduced Bax protein levels and increased Bcl-2 protein levels in the post-ischemic brains. These results suggest that GB's neuroprotection is attributable to its anti-inflammatory and anti-apoptotic effect through inhibition of NF-κB.