[Effect of ultraviolet irradiation on the proliferation of acute promyelocytic leukemia cells under hypoxic conditions and related mechanisms].

OBJECTIVE: To study the effect of 280 nm-LED ultraviolet irradiation on the proliferation of acute promyelocytic leukemia (APL) HL-60 cells under hypoxic conditions and related mechanism. METHODS: HL-60 cells in the logarithmic growth phase were selected and divided into control, hypoxia, ultraviolet and hypoxia+ultraviolet groups. The cells in the hypoxia group were treated with cobalt chloride (with a final concentration of 150 µmol/L), those in the ultraviolet group were irradiated by 280 nm-LED ultraviolet with an energy intensity of 30 J/m2, and those in the hypoxia+ultraviolet group were treated with cobalt chloride and then irradiated by 280 nm-LED ultraviolet. After 48 hours of treatment, the cells were placed under an invert microscope to observe cell morphology. CCK-8 assay was used to measure the inhibition rate of cell proliferation. Annexin V-FITC/PI double staining flow cytometry was used to evaluate cell apoptosis. Quantitative real-time PCR was used to measure the mRNA expression of Bcl-2. Each experiment above was repeated three times independently. RESULTS: Compared with the control group, the experimental groups showed shrinkage, decreased brightness, and disordered arrangement of cells, and the number of cells decreased over the time of culture. There were significant differences in the inhibition rate of cell proliferation and cell apoptosis rate among the groups (P<0.01), and the hypoxia+ultraviolet group showed the strongest inhibition of cell proliferation and induction of cell apoptosis, followed by the ultraviolet group and the hypoxia group. Compared with the control group, the other three groups had a gradual reduction in the mRNA expression of Bcl-2, and the hypoxia+ultraviolet group had a significantly greater reduction than the hypoxia and ultraviolet groups (P<0.01). CONCLUSIONS: Both hypoxia and ultraviolet irradiation can inhibit the proliferation of HL-60 cells and induce cell apoptosis, and ultraviolet irradiation has a better effect on proliferation inhibition and cell apoptosis under hypoxic conditions than under normoxic conditions, possibly by downregulating the mRNA expression of Bcl-2.

Rotenone could activate microglia through NFκB associated pathway.

Parkinson's disease (PD) is a common neurodegenerative disease, and its etiology remains obscure. Increasing evidence has suggested an important role for environmental factors such as exposure to pesticides in increasing the risk of developing PD and inflammation is the early incident during the process of PD. In this study, we measure the pro-inflammatory cytokines by enzyme-linked immunosorbnent assay and RT-PCR methods; analyze the reactive oxygen species by DCFH-DA; detected nuclear factor κB (NFκB) translocation by western blot and immunofluorescence methods; and analyze the phosphorylation of mitogen-activated protein (MAP) kinase and protein level of Nurr1 by western blot. Results showed that rotenone could induce tumor neurosis factor α (TNFα) and interleukin 1ß (IL-1ß) release from BV-2 cells, enhance TNFα and IL-1ß mRNA levels in substantia nigra lesioned by rotenone; also, rotenone could increase the phosphorylation of inhibitor of κB (IκB), extracellular regulated protein kinase , c-Jun N-terminal kinase, p38 MAP kinases and promote p65 subunit of NFκB translocation to nuclear; at the same time, rotenone could decrease the protein level of Nurr1 in nuclear. So, rotenone exerted toxicity through activating microglia, and its mechanism might be associated with NFκB signal pathway.

[Mifepristone repairs alteration of learning and memory abilities in rat model of depression].

This study is to investigate the amelioration effect of glucocorticoid receptor (GR) antagonist mifepristone on the changes of learning and memory abilities in rat model of depression. In the present study, a 35-day rat chronic unpredictable stress (CUS) model was used to observe both depression-like behaviors with sucrose preference test and open-field test and learning and memory-associated behaviors with Morris water maze test. A total of 45 male adult Sprague-Dawley rats were randomly assigned to three groups of equal size: control group (CON); CUS group (CUS); CUS + mifepristone group (CM). Animals in CM group were first exposed to CUS for 14 days, and then were administered with 50 mg x kg(-1) x d(-1) of mifepristone with continued CUS procedure. Corticosterone EIA Kit was used to detect the concentration of plasma corticosterone (CORT). Nissl staining was used to observe the structure of hippocampus. The results demonstrated that CUS exposure induced both depressive-like and learning and memory-associated behaviors and these deficits were reversed by mifepristone. Compared to CON group, the concentration of plasma CORT increased significantly in CUS group. CUS exposure damaged the structure of hippocampus, whereas mifepristone had an amelioration effect. Together, the structural deficits of hippocampus resulting from long-term stress exposure, which could contribute to the impairment of learning and memory in depression, are reversed by the GR receptor antagonist mifepristone.

Polygalasaponin F induces long-term potentiation in adult rat hippocampus via NMDA receptor activation.

AIM: To investigate the effect and underlying mechanisms of polygalasaponin F (PGSF), a triterpenoid saponin isolated from Polygala japonica, on long-term potentiation (LTP) in hippocampus dentate gyrus (DG) of anesthetized rats. METHODS: Population spike (PS) of hippocampal DG was recorded in anesthetized male Wistar rats. PGSF, the NMDAR inhibitor MK801 and the CaMKII inhibitor KN93 were intracerebroventricularly administered. Western blotting analysis was used to examine the phosphorylation expressions of NMDA receptor subunit 2B (NR2B), Ca(2+)/calmodulin-dependent kinase II (CaMKII), extracellular signal-regulated kinase (ERK), and cAMP response element-binding protein (CREB). RESULTS: Intracerebroventricular administration of PGSF (1 and 10 µmol/L) produced long-lasting increase of PS amplitude in hippocampal DG in a dose-dependent manner. Pre-injection of MK801 (100 µmol/L) or KN93 (100 µmol/L) completely blocked PGSF-induced LTP. Furthermore, the phosphorylation of NR2B, CaMKII, ERK, and CREB in hippocampus was significantly increased 5-60 min after LTP induction. The up-regulation of p-CaMKII expression could be completely abolished by pre-injection of MK801. The up-regulation of p-ERK and p-CREB expressions could be partially blocked by pre-injection of KN93. CONCLUSION: PGSF could induce LTP in hippocampal DG in anesthetized rats via NMDAR activation mediated by CaMKII, ERK and CREB signaling pathway.

Polygalasaponin XXXII from Polygala tenuifolia root improves hippocampal-dependent learning and memory.

AIM: The aim of this study was to investigate the cognition-enhancing activity and underlying mechanisms of a triterpenoid saponin (polygalasaponin XXXII, PGS32) isolated from the roots of Polygala tenuifolia Willd. METHODS: The Morris water maze was used to evaluate the spatial learning and memory of mice. To detect the basic properties of synaptic transmission and long-term potentiation (LTP) in the dentate gyrus of rats, electrophysiological recordings were made of evoked potentials. Western blotting analysis and immunofluorescence assays were used to determine the phosphorylation of extracellular signal-regulated kinase (ERK), cAMP response element-binding protein (CREB), synapsin I and the expression of brain derived neurotrophic factor (BDNF). RESULTS: When administered at 0.125, 0.5, or 2 mg/kg, PGS32 could significantly prevent scopolamine-induced cognitive impairments in mice. Intracerebroventricular (icv) administration of PGS32 greatly enhanced basic synaptic transmission in the dentate gyrus of rats and induced LTP. In primary hippocampal neurons, as well as in the hippocampus of maze-trained mice, PGS32 activated the mitogen-activated protein (MAP) kinase cascade by promoting phosphorylation of ERK, CREB and synapsin I. The expression of BDNF was also greatly enhanced in the hippocampus. CONCLUSION: Our findings suggest that PGS32 can improve hippocampus-dependent learning and memory, possibly through improvement of synaptic transmission, activation of the MAP kinase cascade and enhancement of the level of BDNF. Therefore, PGS32 shows promise as a potential cognition-enhancing therapeutic drug.

[MPP+ decreased BDNF expression in PC12 cells].

The aim of this study is to investigate the neurotoxic effect and mechanism of 1-methyl-4-phenylpyridinium (MPP+) on PC12 cells. MTT assay was used to investigate cell viability, Western blotting assay was performed to observe the protein level and phosphorylation, and dual-luciferase assay was used to study the transactivation. The experiment showed that MPP+ could decrease cell viability significantly in a dose-dependent manner and could decrease BDNF protein level, depress the phosphorylation of ERK, and attenuate the phosphorylation and transactivation of CREB, which is one of transcription factors of BDNF, but did not affect the activity of CaMK II in PC12 cells. So MPP+ might decrease BDNF protein level through MAPK/ERK signal pathway.

Emergency department use among patients from residential aged care facilities under a Hospital in the Nursing Home scheme in public hospitals in Queensland Australia.

BACKGROUND: Hospital emergency department (ED) use by patients from residential aged care facilities (RACFs) is not always appropriate, and this calls for interventions to avoid some unnecessary uses. This study aims to compare patterns of ED use by RACF patients with and without a Hospital in the Nursing Home (HiNH) program. METHODS: RACF patients presenting to EDs of a hospital with and a hospital without this program during pre- and post-intervention periods were included. Data on patient demographics and ED presentation characteristics were obtained from the Emergency Department Information System database, and were analysed by descriptive and comparative statistics. RESULTS: In both hospitals, most RACF residents presenting to EDs were aged between 75-94 years, female, triaged at scale 3 to 5, and transferred on weekdays and during working hours. Almost half of them were subsequently admitted to hospitals. In accordance with the ICD-10-AM diagnostic coding system, diagnoses that consistently ranked among the top three reasons for visiting the two hospitals before and after intervention included Chapter XIX: injury and poisoning and Chapter X: respiratory diseases. Associated with the intervention, significant decreases in the numbers of presentations per 1 000 RACF beds were identified among patients diagnosed with Chapter XI: digestive diseases [rate ratio (95%CI): 0.09 (0.04, 0.22); P<0.0001] and Chapter XXI: factors influencing health status and contact with health services [rate ratio (95%CI): 0.22 (0.07, 0.66); P=0.007]. CONCLUSION: The HiNH program may reduce the incidence of RACF residents visiting EDs for diagnoses of Chapter XI and Chapter XXI.

Doctor's Knowledge and Practices of Traumatic Brain Injury Management in Chinese Prehospital Settings.

OBJECTIVES: The incidence and mortality of traumatic brain injury (TBI) has increased rapidly in the last decade in China. Appropriate ambulance service can reduce case-fatality rates of TBI significantly. This study aimed to explore the factors (age, gender, education level, clinical experience, professional title, organization, specialty before prehospital care, and training frequency) that could influence prehospital doctors' knowledge level and practices in TBI management in China, Hubei Province. METHODS: A cross-sectional questionnaire survey was conducted in two cities in Hubei Province. The self-administered questionnaire consisted of demographic information and questions about prehospital TBI management. Independent samples t-test and one-way ANOVA were used to analyze group differences in the average scores in terms of demographic character. General linear regression was used to explore associated factors in prehospital TBI management. RESULTS: A total of 56 questionnaires were handed out and 52 (93%) were returned. Participants received the lowest scores in TBI treatment (0.64; SD=0.08) and the highest scores in TBI assessment (0.80; SD=0.14). According to the regression model, the education level was associated positively with the score of TBI identification (P=.019); participants who worked in the emergency department (ED; P=.011) or formerly practiced internal medicine (P=.009) tended to get lower scores in TBI assessment; participants' scores in TBI treatment were associated positively with the training frequency (P=.011); and no statistically significant associated factor was found in the overall TBI management. CONCLUSION: This study described the current situation of prehospital TBI management. The prehospital doctors' knowledge level and practices in TBI management were quantified and the influential factors hidden underneath were explored. The results indicated that an appropriate continuing medical education (CME) program enables improvement of the quality of ambulance service in China.

Environment-contact administration of rotenone: A new rodent model of Parkinson's disease.

Epidemiological studies suggest an association between pesticides and the incidence of Parkinson's disease (PD). Individuals are likely to be exposed to numerous natural or synthetic environmental agents by ingestion, inhalation, or skin contact. Here, we describe a novel environment-contact administration of rotenone model, in which male C57BL/6 mice (15 per group per time-point) were placed in one bedding-free, rotenone-applied cage for 2h every day over a period of 2-6 weeks, mimicking the common ways a person may be exposed to pesticides. Our results showed that rotenone exposure had no detrimental effect on body weights of mice during 6 weeks, nor did it cause systemic toxicity (HPLC analysis of rotenone in blood and brain, as well as complex I activity measurements in brain and muscle), but it caused significant impairments in motor function (open field test, pole test, and rotarod test) from 4 weeks that were responsive to apomorphine. Accordingly, rotenone caused significant dopamine depletion from the striatum (HPLC analysis), nigrostriatal degeneration (quantitative tyrosine hydroxylase immunohistochemistry and western blot), and accumulation of α-synuclein in the substantia nigra and striatum (α-synuclein immunohistochemistry) in a time-dependent manner. In addition, rotenone-exposed mice also developed deficits in gastrointestinal and olfactory function (fecal pellet output and buried food pellet test) prior to the motor dysfunction. Furthermore, we observed that α-synuclein accumulated in the anterior olfactory nucleus and the enteric nervous system at 2 weeks. In summary, this novel rotenone model was able to reproduce many key aspects of PD progression. Therefore, it provides new insight into how environmental factors could trigger PD and provides a useful tool for studying PD pathogenesis and testing neuroprotective strategies.