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 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.

[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.

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.

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.

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.

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.