Students' and Teachers' Perspective on the Implementation of Online Medical Education in China: A Qualitative Study.

OBJECTIVE: Due to the quarantine measures during the outbreak of COVID-19, medical schools in China had to shift to online education overnight. Researchers wanted to survey the online medical education status quo and find out the underlying challenges and probable solutions in terms of online medical education to better understand improving and developing medical education in China. METHODS: Researchers distributed self-administered and piloted surveys regarding the implementation of online medical education on WeChat and Wenjuanxing. Researchers distributed three phases of online surveys to the undergraduate medical students, and one online survey to the medical teachers on phase three. RESULTS: Online medical education was carried out smoothly in China. Seventy-six percent of the students were satisfied with online medical education, and it hardly changed after a month. Courses with the quiz and live-stream courses were rare compared with courses incorporated with other elements. Most parents would remind their children to study online at home. At first, the biggest challenge of learning online was the lagging platform. Nevertheless, as time went by, the major challenge became the learning motivation. Most students thought it necessary to re-teach face-to-face after online education, while most teachers did not think so. CONCLUSION: Generally speaking, online medical education was satisfying for both students and teachers, although online courses' diversity with different forms and elements could be enhanced. Infrastructure construction should be considered first for the schools intended to promote online medical education. If the infrastructure were ready, learning motivation would become the biggest challenge for online medical education. Online medical education efficacy evaluation tools need to be developed in the future to narrow the discrepancy of the evaluation between teachers and students.

Low serum uric acid levels in patients with multiple sclerosis and neuromyelitis optica: An updated meta-analysis.

OBJECTIVES: To evaluate the association between serum uric acid (UA) levels and patients with MS and NMO. METHODS: The PubMed, Web of Science and Cochrane Library database were searched for relevant studies. Pooled standardized mean difference (SMD) and 95% confidence interval (CI) were used as effect size. Subgroup analysis was performed by gender, country, disease durations, scores of EDSS, detection method and clinical classification. RESULTS: A total of 10 case-control studies involving 1537 patients (1308 MS patients, 229 NMO patients) and 908 healthy controls were included. We found the serum UA levels of patients with MS and NMO were significantly lower compared to those of healthy controls (SMD=-0.52, 95%CI,-0.81 to -0.24). In the subgroup analysis, there was no significant difference between serum UA levels in patients and healthy controls in European subgroup (SMD=-0.32, 95%CI,-0.78 to 0.14). Additionally, we found that serum UA levels were higher in MS and NMO patients than in healthy controls in EDSS>3.5 subgroup (SMD=-0.38, 95%CI,-0.58 to -0.19), but not in EDSS≤3.5 subgroup (SMD=-0.35, 95%CI,-0.97 to 0.27). Patients of relapsing group had significant lower serum UA levels than patients of remitting group (SMD=0.70, 95%CI, 0.19-1.21). CONCLUSION: Patients with MS and NMO showed lower serum UA levels when compared with healthy controls. Serum UA might be a potential diagnostic biomarker for MS and NMO.

Involvement of calcium/calmodulin-dependent protein kinase II in methamphetamine-induced neural damage.

Methamphetamine (METH), an illicit drug, is widely abused in many parts of the world. Mounting evidence shows that METH exposure contributes to neurotoxicity, particularly for the monoaminergic neurons. However, to date, only a few studies have tried to unravel the mechanisms involved in METH-induced non-monoaminergic neural damage. Therefore, in the present study, we tried to explore the mechanisms for METH-induced neural damage in cortical neurons. Our results showed that METH significantly increased intracellular [Ca(2) (+) ]i in Ca(2) (+) -containing solution rather than Ca(2) (+) -free solution. Moreover, METH also upregulated calmodulin (CaM) expression and activated CaM-dependent protein kinase II (CaMKII). Significantly, METH-induced neural damage can be partially retarded by CaM antagonist W7 as well as CaMKII blocker KN93. In addition, L-type Ca(2) (+) channel was also proved to be involved in METH-induced cell damage, as nifedipine, the L-type Ca(2) (+) channel-specific inhibitor, markedly attenuated METH-induced neural damage. Collectively, our results suggest that Ca(2) (+) -CaM-CaMKII is involved in METH-mediated neurotoxicity, and it might suggest a potential target for the development of therapeutic strategies for METH abuse. Copyright © 2016 John Wiley & Sons, Ltd.

Insulin signaling disruption in male mice due to perinatal bisphenol A exposure: Role of insulin signaling in the brain.

Bisphenol A (BPA), an environmental estrogenic endocrine disruptor, is widely used for producing polycarbonate plastics and epoxy resins. Available data have shown that perinatal exposure to BPA contributes to peripheral insulin resistance, while in the present study, we aimed to investigate the effects of perinatal BPA exposure on insulin signaling and glucose transport in the cortex of offspring mice. The pregnant mice were administrated either vehicle or BPA (100 µg/kg/day) at three perinatal stages. Stage I: from day 6 of gestation until parturition (P6-PND0 fetus exposure); Stage II: from lactation until delactation (PND0-PND21 newborn exposure) and Stage III: from day 6 of pregnancy until delactation (P6-PND21 fetus and newborn exposure). At 8 months of age for the offspring mice, the insulin signaling pathways and glucose transporters (GLUTs) were detected. Our data indicated that the insulin signaling including insulin, phosphorylated insulin receptor (IR), phosphorylated protein kinase B (p-AKT), phosphorylated glycogen synthase kinase 3ß (p-GSK3ß) and phosphorylated extracellular signal regulated protein kinase (p-ERK) were significantly decreased in the brain. In parallel, GLUTs (GLUT1/3/4) were obviously decreased as well in BPA-treated group in mice brain. Noteworthily, the phosphorylated tau (p-tau) and amyloid precursor protein (APP) were markedly up-regulated in all BPA-treated groups. These results, taken together, suggest the adverse effects of BPA on insulin signaling and GLUTs, which might subsequently contribute to the increment of p-tau and APP in the brain of adult offspring. Therefore, perinatal BPA exposure might be a risk factor for the long-term neurodegenerative changes in offspring male mice.

Integrated long non-coding RNA analyses identify novel regulators of epithelial-mesenchymal transition in the mouse model of pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic fatal lung disease characterized by aberrant accumulation of fibroblast population and deposition of extra cellular matrix. Increasing evidence support that epithelial-mesenchymal transition (EMT) of alveolar epithelial cells is a critical process in the pathogenesis of IPF. Although delivery of bleomycin to induce acute lung injury is the most well-studied animal model of pulmonary fibrosis, there is considerable interest to pursue other models to understand the common and/or specific pathological mechanisms. In this study, we established a mouse model of pulmonary injury and progressive interstitial fibrosis via intraperitoneal injection of paraquat, a widely used herbicide known to cause pulmonary fibrosis in human. Using transcriptome sequencing and microarray analysis, we profiled expression of long non-coding RNAs (lncRNAs) and identified 513 up-regulated and 204 down-regulated lncRNAs in paraquat-induced fibrotic lung tissues. Gene ontology analysis revealed that the differentially expressed lncRNAs are implicated in cell differentiation, epithelium morphogenesis and wound healing, pathways closely associated with EMT. Furthermore, we identified the evolutionally conserved target genes of two up-regulated lncRNAs, uc.77 and 2700086A05Rik, as Zeb2 and Hoxa3, respectively, both of which are important modulators of EMT. Consistently, overexpression of uc.77 or 2700086A05Rik in human lung epithelial cells induced EMT as demonstrated by changes in gene and protein expression of various EMT markers and cell morphology. Collectively, our results uncovered a crucial role of lncRNA in the regulation of EMT during lung fibrosis and provide potential avenues for the discovery of novel molecular markers and therapeutic targets for IPF.

Urinary trypsin inhibitor attenuates LPS-induced endothelial barrier dysfunction by upregulation of vascular endothelial-cadherin expression.

INTRODUCTION: Urinary trypsin inhibitor (UTI) decreases inflammatory cytokine levels and mortality in experimental animal models of inflammation. Here, we observed the effect of UTI on lipopolysaccharide (LPS)-induced hyperpermeability in human umbilical vein endothelial cells (HUVECs) and explored the role of vascular endothelial-cadherin (VE-cadherin) in its effect. METHODS: The effect of UTI on endothelial barrier hyperpermeability was detected by an electrical cell-substrate impedance sensing (ECIS) system and a transwell chamber system. The expression of VE-cadherin in HUVECs was examined by real-time PCR and western blot. RESULTS: We demonstrated that the alleviation of LPS-induced barrier dysfunction could be achieved by pretreatment with 3000 U/mL of UTI. VE-cadherin monoclonal antibody (mAb) could inhibit the protective effects. UTI maintained VE-cadherin expression by increasing protein stability at both the transcriptional and post-transcriptional levels. Meanwhile, VE-cadherin expression on the cell surface increased when the cells were pretreated with UTI. Furthermore, pretreatment with UTI decreased the phosphorylation of VE-cadherin at Tyr658 but not Tyr731. CONCLUSIONS: Our data show that prophylactic UTI maintains the endothelial barrier function, increases VE-cadherin expression, and inhibits the phosphorylation of VE-cadherin at Tyr658 under inflammatory conditions. It suggests a scientific and potential clinical therapeutic importance of UTI in treatment of inflammatory disorders.

Target of HIV-1 Envelope Glycoprotein gp120-Induced Hippocampal Neuron Damage: Role of Voltage-Gated K(+) Channel Kv2.1.

Human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein 120 (gp120) has been reported to be toxic to the hippocampal neurons, and to be involved in the pathogenesis of HIV-1-associated neurocognitive disorders (HAND). Accumulating evidence has demonstrated that voltage-gated potassium (Kv) channels, especially the outward delayed-rectifier K(+) (Ik) channels, play a critical role in gp120-induced cortical neuronal death in vitro. However, the potential mechanisms underlying the hippocampal neuronal injury resulted from gp120-mediated neurotoxicity remain poorly understood. Using whole-cell patch clamp recording in cultured hippocampal neurons, this study found that gp120 significantly increased the outward delayed-rectifier K(+) currents (Ik). Meanwhile, Western blot assay revealed that gp120 markedly upregulated Kv2.1 protein levels, which was consistent with the increased Ik density. With Western blot and terminal deoxynucleotidyl transferase dUTP nick end labeling assays, it was discovered that gp120-induced neuronal injury was largely due to activation of Kv2.1 channels and resultant apoptosis mediated by caspase-3 activation, as the pharmacological blockade of Kv2.1 channels largely attenuated gp120-induced cell damage and caspase-3 expression. Moreover, p38 MAPK was demonstrated to participate in gp120-induced hippocampal neural damage, since p38 MAPK antagonist (SB203580) partially abrogated gp120-induced Kv2.1 upregulation and neural apoptosis. Taken together, these results suggest that gp120 induces hippocampal neuron apoptosis by enhancement of the Ik, which might be associated with increased Kv2.1 expression via the p38 MAPK pathway.

The toxic effects of Bisphenol A on the mouse spermatocyte GC-2 cell line: the role of the Ca2+-calmodulin-Ca2+/calmodulin-dependent protein kinase II axis.

Bisphenol A (BPA), an endocrine-disrupting chemical (EDC), is known to induce male reproductive toxicity in rodents. However, its toxic effects on the germ cells are still poorly understood. It has been proposed that Ca(2+) homeostasis and Ca(2+) sensors, including calmodulin (CaM) and calmodulin-dependent protein kinase II (CaMKII), play critical roles in spermatogenesis. Therefore, in the present study, we aimed to investigate whether a perturbation in Ca(2+)-CaM-CaMKII signaling was involved in the BPA-induced injury to mouse spermatocyte GC-2spd (ts) (GC-2) cells. Our results showed that BPA (range from 0.2 to 20 µM) induced obvious GC-2 cell injury, including decreased cell viability, the release of mitochondrial cytochrome c and the activation of caspase-3. However, these processes could be partially abrogated by pretreatment with a Ca(2+) chelator (BAPTA/AM), a CaM antagonist (W7) or a CaMKII inhibitor (KN93). These results, taken together, indicate that BPA exposure contributes to male germ cell injury, which may be partially mediated through a perturbation in Ca(2+)/CaM/CaMKII signaling and the mitochondrial apoptotic process.

Involvement of mitogen-activated protein kinase and NF-κB signaling pathways in perfluorooctane sulfonic acid-induced inflammatory reaction in BV2 microglial cells.

Microglial activation is closely related to the pathogenesis of neurodegenerative diseases by producing proinflammatory cytokines. Perfluorooctane sulfonic acid (PFOS), known as an emerging persistent organic pollutant, is reported to disturb human immune homeostasis; however, whether it affects cytokine production or the immune response in the central nervous system remains unclear. The present study was aimed to explore whether PFOS contributed to inflammatory action and to investigate the corresponding mechanisms in BV2 microglia. PFOS-mediated morphologic changes, cytokine responses and signaling events were examined by light microscopy, real-time polymerase chain reaction, enzyme-linked immunosorbent assay and Western blot assays. Our results indicated that PFOS increased BV2 cells activation and simultaneously increased tumor necrosis factor alpha and interleukin-6 expression. In addition, the c-Jun N-terminal protein kinase inhibitor (SP600125), as well as ERK1/2 blocker (PD98059), transcriptionally at least, displayed anti-inflammatory properties on PFOS-elicited cytokine responses. Moreover, the inflammatory transcription factor NF-κB was specifically activated by PFOS as well. These results, taken together, suggested that PFOS exerts its functional effects on the response of microglial cell activation via, in part, the c-Jun N-terminal protein kinase, ERK and NF-κB signaling pathways with its subsequent influence on proinflammatory action.

Effects of Bisphenol A on glucose homeostasis and brain insulin signaling pathways in male mice.

The potential effects of Bisphenol A (BPA) on peripheral insulin resistance have recently gained more attention, however, its functions on brain insulin resistance are still unknown. The aim of the present study was to investigate the effects of BPA on insulin signaling and glucose transport in mouse brain. The male mice were administrated of 100 µg/kg/day BPA or vehicle for 15 days then challenged with glucose and insulin tolerance tests. The insulin levels were detected with radioimmunoassay (RIA), and the insulin signaling pathways were investigated by Western blot. Our results revealed that BPA significantly increased peripheral plasma insulin levels, and decreased the insulin signals including phosphorylated insulin receptor (p-IR), phosphorylated insulin receptor substrate 1 (p-IRS1), phosphorylated protein kinase B (p-AKT), phosphorylated glycogen synthase kinase 3ß (p-GSK3ß) and phosphorylated extracellular regulated protein kinases (p-ERK1/2) in the brain, though insulin expression in both hippocampus and profrontal cortex was increased. In parallel, BPA exposure might contribute to glucose transport disturbance in the brain since the expression of glucose transporters were markedly decreased. In conclusion, BPA exposure perturbs the insulin signaling and glucose transport in the brain, therefore, it might be a risk factor for brain insulin resistance.

MAPK and NF-κB pathways are involved in bisphenol A-induced TNF-α and IL-6 production in BV2 microglial cells.

Microglial activation has been reported to play an important role in neurodegenerative diseases by producing pro-inflammatory cytokines. Bisphenol A (BPA, 2,2-bis (4-hydroxyphenyl) propane), known as a ubiquitous endocrine-disrupting chemical, is reported to perform both mimic- and anti-estrogen properties; however, whether it affects cytokine production or immune response in central nervous system remains unclear. The present study was aimed to explore whether BPA was involved in inflammatory action and to investigate the potential mechanisms in microglial cells. BV2, the murine microglial cell line, was used in the present work as the cell model. BPA-associated morphologic changes, cytokine responses, and signaling events were examined using immunofluorescence analysis, real-time PCR, enzyme-linked immunosorbent assay, and western blot. Our results indicated that BPA increased BV2 cells activation and simultaneously elevated tumor necrosis factor-α and interleukin 6 expression, which could be partially reversed by estrogen receptor antagonist, ICI182780. In addition, the c-Jun N-terminal protein kinase (JNK) inhibitor (SP600125), rather than ERK1/2 blocker (PD98059), displayed anti-inflammatory properties on BPA-elicited cytokine responses. Moreover, the inflammatory transcription factor NF-κB was specifically activated by BPA as well. These results, taken together, suggested that BPA may have functional effects on the response of microglial cell activation via, in part, the estrogen receptor, JNK, ERK mitogen-activated protein kinase, and NF-κB signaling pathways with its subsequent influence on pro-inflammatory action.

Dexmedetomidine inhibits inducible nitric oxide synthase in lipopolysaccharide-stimulated microglia by suppression of extracellular signal-regulated kinase.

OBJECTIVE: Dexmedetomidine (DEX) has been implicated in modulating the inflammatory response in central nervous system (CNS). However, the mechanism is still poorly understood. In this study, we evaluate the effects of DEX on lipopolysaccharide (LPS)-induced microglia activation and elucidate its possible signaling pathway involved in its anti-inflammatory effects. METHODS: BV2 and primary microglia were pretreated with various concentrations of DEX (0·01, 0·1, 1, and 10 µM) and/or PD98059 for 1 hour, then microglia were incubated with LPS (1 µg/ml) for 24 hours. Nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression were measured by Griess reagent and real-time polymerase chain reaction. Furthermore, two intracellular signaling cascades including extracellular signal-regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK) were investigated by western blot analysis. RESULTS: Dexmedetomidine significantly attenuated LPS-induced NO production and iNOS expression in both BV2 cells and primary microglial cells. Lipopolysaccharide activated both ERK1/2 and JNK signal pathways; however, DEX exerted a specific inhibitory effect on ERK1/2 rather than JNK. Intriguingly, treatment of primary microglia and BV2 cells with DEX in combination with ERK1/2 inhibitor (PD98059) enhanced attenuation of LPS-induced NO production and iNOS expression. DISCUSSION: Dexmedetomidine attenuates NO and iNOS accumulation by inhibiting extracellular signal-regulated kinase (ERK) activation in both BV2 cells and primary microglial cells.

α-ENaC, a therapeutic target of dexamethasone on hydrogen sulfide induced acute pulmonary edema.

Acute pulmonary edema (APE) is one of the fatal outcomes after exposure to high levels of hydrogen sulfide (H2S), available evidence suggest that dexamethasone (DXM), a potent anti-inflammatory agent, has been widely used or proposed as a therapeutic approach for H2S-induced APE in clinical practice, however, the underlying mechanism remains poorly understood. Ample evidence suggest that epithelial Na(+) channel, especially for the subunit α-epithelial Na(+) channel (α-ENaC) plays a critical role in alveolar fluid clearance. Therefore, the present study is undertaken to investigate the effects of DXM on α-ENaC following H2S exposure. The Sprague Dawley rats were exposed to H2S to establish APE model, in parallel, A549 cells were treated with NaHS to establish cell model. In vivo study, we found that DXM significantly attenuated H2S-induced lung histopathological changes and alveolar fluid clearance decrement, however, these preventive effects of DXM can be obviously counteracted by the mifepristone (MIF), the glucocorticoid receptor (GR) blocker. Moreover, DXM markedly attenuated H2S-mediated α-ENaC down-regulation, and similarly, the process can be partially retarded by MIF. Furthermore, DXM obviously prevented H2S-mediated ERK1/2 activation both in vitro and in vivo study. These results, taken together, suggested that DXM exerted protective effects on H2S-induced APE, and α-ENaC might be a potential therapeutic target for APE induced by H2S.

Association between the XRCC3 Thr241Met polymorphism and breast cancer risk: an updated meta-analysis of 36 case-control studies.

BACKGROUND: The X-ray repair cross-complementing group 3 (XRCC3) is a highly suspected candidate gene for cancer susceptibility. Attention has been drawn upon associations of the XRCC3 Thr241Met polymorphism with breast cancer risk. However, the previous published findings remain controversial. Hence, we performed a meta-analysis to accurately evaluate any association between breast cancer and XRCC3 T241M (23, 812 cases and 25, 349 controls) in different inheritance models. MATERIALS AND METHODS: PubMed and Web of Science databases were searched systematically until December 31, 2013 to obtain all the records evaluating the association between the XRCC3 Thr241Met polymorphism and breast cancer risk. Crude odds ratios (ORs) together with 95% confidence intervals (CIs) were used to assess the strength of associations. RESULTS: When all eligible studies were pooled into the meta analysis of XRCC3 T241M polymorphism, a significantly increased breast cancer risk was observed in heterozygote comparison (OR=1.06, 95%CI=1.01-1.12). No significant associations were found in other models. In subgroup analysis, this polymorphism seemed to be associated with elevated breast risk in Asians. No publication bias was detected. CONCLUSIONS: This meta-analysis suggests that the T241M polymorphism confers a weakly increased breast cancer risk. A study with the larger sample size is needed to further evaluate gene-gene and gene-environment interactions of the XRCC3 T241M polymorphism with breast cancer risk.

Involvement of CaM-CaMKII-ERK in bisphenol A-induced Sertoli cell apoptosis.

Bisphenol A (BPA), one of the most prevalent chemicals for daily use, has been reported as a xenoestrogen to induce reproductive toxicity, but its mechanism is poorly understood. In the present study, we aimed to explore whether CaM-CaMKII-ERK1/2 signaling pathway was involved in BPA-induced Sertoli cells injury via the mitochondrial apoptotic pathway. TM4 cells were cultured with 0, 0.02, 0.2, 2.0, 20µM BPA, and cell viability, mitochondrial function and CaM-CaMKII-ERK1/2 signal pathway were examined. With the MTT assay, BPA was found to suppress cell viability in a dose- and time-dependent manner. Moreover, mitochondrial mass loss, membrane potential decrease, cytochrome c release, Bcl-2 family members down-regulation and caspases-3 up-regulation were obviously observed when the TM4 cells were exposed to BPA. Additionally, the expression of calmodulin (CaM) and phosphorylation of calcium/calmodulin dependent kinase II (CaMKII) significantly increased, and pretreatment with 10µM antagonist of CaM (W-7) or CaMKII (KN62) prevented cell damage through mitochondrial apoptotic pathway. In parallel, ERK1/2 pathway was proved to participate in BPA-induced cell damage, since W-7 and KN62 partially suppressed ERK1/2 activation, and PD98059, the ERK1/2 antagonist, significantly attenuated BPA-induced cell damage. These data, taken together, indicated that CaM-CaMKII-ERK axis might transmit apoptotic signals to the mitochondria during BPA-induced cell apoptosis. By exploring the mechanisms of the Ca(2+) homeostasis and the corresponding proteins, our study provides new insight into BPA-induced reproductive toxicity.

Effect of methamphetamine on the microglial damage: role of potassium channel Kv1.3.

Methamphetamine (Meth) abusing represents a major public health problem worldwide. Meth has long been known to induce neurotoxicity. However, the mechanism is still remained poorly understood. Growing evidences indicated that the voltage-gated potassium channels (Kv) were participated in neuronal damage and microglia function. With the whole cell patch clamp, we found that Meth significantly increased the outward K⁺ currents, therefore, we explored whether Kv1.3, one of the major K⁺ channels expressed in microglia, was involved in Meth-induced microglia damage. Our study showed that Meth significantly increased the cell viability in a dose dependent manner, while the Kv blocker, tetraethylamine (TEA), 4-Aminopyridine (4-AP) and Kv1.3 specific antagonist margatoxin (MgTx), prevented against the damage mediated by Meth. Interestingly, treatment of cells with Meth resulted in increasing expression of Kv1.3 rather than Kv1.5, at both mRNA and protein level, which is partially blocked by MgTx. Furthermore, Meth also stimulated a significant increased expression of IL-6 and TNF-α at protein level, which was significantly inhibited by MgTx. Taken together, these results demonstrated that Kv1.3 was involved in Meth-mediated microglial damage, providing the potential target for the development of therapeutic strategies for Meth abuse.

Dexmedetomidine inhibits tumor necrosis factor-alpha and interleukin 6 in lipopolysaccharide-stimulated astrocytes by suppression of c-Jun N-terminal kinases.

Astrocytes play an important role in immune regulation in the central nervous system (CNS). Dexmedetomidine (DEX) has been reported to exert anti-inflammatory effects on astrocytes stimulated by lipopolysaccharide (LPS) both in vitro and in vivo studies. However, the underlying molecular mechanisms remain poorly understood. This study was designed to evaluate the effects of DEX on tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) gene expressions in LPS-challenged astrocytes. Moreover, c-Jun N-terminal kinases (JNKs) and p38 mitogen-activated protein kinase (MAPK) pathways in LPS-challenged astrocytes were also investigated. In the present study, astrocytes were stimulated with LPS in the absence and presence of various concentrations of DEX. With real-time PCR assay, we found that LPS significantly increased expressions of TNF-α and IL-6 in mRNA level; however, these effects could be attenuated by DEX. Furthermore, JNK pathway might be involved in LPS-induced astrocyte activation because JNK phosphorylation was significantly increased, and the inhibition of this pathway mediated by DEX as well as SP600125 (JNK inhibitor) decreased TNF-α and IL-6 expressions. Moreover, p38 MAPK was also activated by LPS; however, this pathway seemed to have not participated in DEX-mediated LPS-induced inflammation. These results, taken together, suggest that JNK rather than p38 MAPK signal pathway, provides the potential target for the therapeutic effects of DEX for neuronal inflammatory reactions.

Martentoxin, a large-conductance Ca(2+)-activated K(+) channel inhibitor, attenuated TNF-α-induced nitric oxide release by human umbilical vein endothelial cells.

Martentoxin, a 4,046 Da polypeptide toxin purified from the venom of the scorpion Buthus martensii Karsch, has been demonstrated to block large-conductance Ca(2+)-activated K(+) (BKCa) channels; however, its biological roles are still largely unknown. In the present study, we investigated the pharmacological effects of martentoxin on regulating the production of nitric oxide induced by TNF-α in human umbilical vein endothelial cells (HUVECs). We found that, 1, 10 and 100 µmol/L martentoxin decreased nitric oxide production by HUVECs exposed to 10 ng/mL TNF for 6, 12 and 24 hours. We further demonstrated that martentoxin inhibited the activity of iNOS and retarded the down-regulation of eNOS mRNA induced by TNF-α. Therefore, martentoxin could be a potential therapeutic agent for vascular diseases.

Perinatal bisphenol A exposure and adult glucose homeostasis: identifying critical windows of exposure.

Bisphenol A (BPA) is a widespread endocrine-disrupting chemical used as the building block for polycarbonate plastics. Epidemiological evidence has correlated BPA exposure with higher risk of heart disease and type 2 diabetes. However, it remains unknown whether there are critical windows of susceptibility to BPA exposure on the development of dysglycemia. This study was an attempt to investigate the critical windows and the long-term consequences of perinatal exposure to BPA on glucose homeostasis. Pregnant mice were given either vehicle or BPA (100 µg/kg/day) at different time of perinatal stage: 1) on days 1-6 of pregnancy (P1-P6, preimplantation exposure); 2) from day 6 of pregnancy until postnatal day (PND) 0 (P6-PND0, fetal exposure); 3) from lactation until weaning (PND0-PND21, neonatal exposure); and 4) from day 6 of gestation until weaning (P6-PND21, fetal and neonatal exposure). At 3, 6 and 8 months of age, offspring in each group were challenged with glucose and insulin tolerance tests. Then islet morphometry and ß-cell function were measured. The glucose homeostasis was impaired in P6-PND0 mice from 3 to 6 months of age, and this continued to 8 months in males, but not females. While in PND0-PND21 and P6-PND21 BPA-treated groups, only the 3-month-old male offspring developed glucose intolerance. Moreover, at the age of 3 months, perinatal exposure to BPA resulted in the increase of ß-cell mass mainly due to the coordinate changes in cell replication, neogenesis, and apoptosis. The alterations of insulin secretion and insulin sensitivity, rather than ß-cell mass, were consistent with the development of glucose intolerance. Our findings suggest that BPA may contribute to metabolic disorders relevant to glucose homeostasis and the effects of BPA were dose, sex, and time-dependent. Fetal development stage may be the critical window of susceptibility to BPA exposure.