[Homocysteine induces calcium overload in neonatal rat atrial cells through activation of sodium current and CaMKⅡδ]

Objective: To investigate the effect and related mechanism of homocysteine (Hcy) on calcium overload in neonatal rat atrial cells (NRICs). Methods: NRICs were assigned to 9 groups after culture for 3 days: (1) control group; (2) Hcy group (0, 50, 100, 200, 500 μmol/L for 48 hours); (3) antioxidant group (NAC, 10 μmol/L for 24 hours); (4) Hcy+NAC group (500 μmol/L Hcy for 48 hours, then treated with 10 μmol/L NAC for 24 hours); (5) calcium/calmodulin dependent protein kinase Ⅱδ (CaMKⅡδ) inhibitor group (KN-93, 3 μmol/L KN-93 for 5 hours); (6) specific sodium current inhibitor group (ELE, 1 μmol/L ELE for 5 hours); (7) Hcy+KN-93 group (500 μmol/L Hcy for 48 hours, then treated with 3 μmol/L KN-93 for 5 hours); (8) Hcy+ELE group (500 μmol/L Hcy for 48 hours, then treated with 1 μmol/L ELE for 5 hours; (9) Hcy+KN-93+ELE group (500 μmol/L Hcy for 48 hours, then treated with 3 μmol/L KN-93 and 1 μmol/L ELE for 5 hours). Moreover, NRICs were also treated with CaMKⅡδ-siRNA lentivirus, and Nav1.5-siRNA lentivirus, negative lentivirus carrier containing green fluorescent protein (GFP) for 24 hours. The MOI values of the three groups were 10. Infection efficiency of lentivirus was determined by observing the percentage of GFP fluorescence under inverted fluorescence microscope after transfection for 24 hours, and cultured regularly with simultaneous Puro screening, then cells were grouped as Hcy+CaMKⅡδ-siRNA group, Hcy+Nav1.5-siRNA group and Hcy+negative group. The concentration of Ca(2+) in NRICs ([Ca(2+)]i) of various groups was detected through Fluo-4/AM fluorescence probe, then 2', 7'- two chlorofluorescein diacetate (DCFH-DA) was used as a probe to detect reactive oxygen species (ROS) in NRICs by flow cytometry. The malondialdehyde (MDA) was detected by the activity of superoxide dismutase (SOD) and xanthine oxidase was detected by thiobarbituric acid colorimetry. The protein and mRNA expression level of CaMKⅡδ and Nav1.5 in NRICs were detected by Western blot and quantitative real-time PCR. Results: (1) ROS, MDA and SOD were similar between NAC group and control group, ROS and MDA were significantly increased, while SOD was significantly reduced in Hcy group in a concentration-dependent manner. (2) [Ca(2+)]i: The level of [Ca(2+)]i was (155.57+7.25), (187.43+13.07), (248.98+27.22) and (307.36+15.09) nmol/L in 50, 100, 200 and 500 μmol/L Hcy groups, which was significantly higher than that in the control group ((123.18+7.24) nmol/L, P<0.01). In addition, the level of [Ca(2+)]i in Hcy+NAC group ((222.87+23.71)nmol/L) was significantly lower than that in Hcy 500 μmol/L group ((305.15+39.45) nmol/L, P<0.05), while [Ca(2+)]i level was similar between NAC group and the control group. (3) The protein expression of CaMKⅡδ and Nav1.5 was significantly upregulated in Hcy groups than in the control group. The protein expression level of CaMKⅡδ-Thr287 was significantly lower in NAC group than in Hcy 500 μmol/L group (P<0.01), however, there was no significant difference on the protein expression levels of CaMKⅡδ-Thr287 and Nav1.5 between NAC group and control group (all P>0.05). (4) The protein expression levels of CaMKⅡδ-Thr287 and the concentration of [Ca(2+)]i were significantly lower in Hcy+KN-93 group and Hcy+KN-93+ELE group than in Hcy 500 μmol/L group (P<0.05). [Ca(2+)]i concentration was significantly lower in Hcy+KN-93 group, Hcy+ELE group and KN-93+ELE+Hcy group than in Hcy 500 μmol/L group (P<0.05). (5) The mRNA and protein expression levels of CaMKⅡδ and Nav1.5 in each group infected with lentivirus: the GFP expression was ideal post lentivirus transfection for 24 hours (up to 90%), which was significantly lower in the CaMKⅡδ-siRNA group and Nav1.5-siRNA group than in the negative infection group (all P<0.05), which was similar between negative infection group and control group (P>0.05). Moreover, the mRNA and protein expression levels of CaMKⅡδ and CaMKⅡδ-Thr287 was significantly lower in Hcy+Nav1.5-siRNA group than in Hcy+negative infection group (P<0.05). The protein and mRNA levels of Nav1.5 were similar between Hcy+CaMKⅡδ-siRNA group and Hcy+negative infection group (P>0.05). Conclusions: Hcy can induce calcium overload in NRICs by increasing oxidative stress, upregulating the sodium channel protein, and activating the late sodium current and phosphorylating CaMKⅡδ.

[Study on bone metabolism in postmenopausal women with idiopathic benign paroxysmal positional vertigo]

Objective: To analyze the bone mineral density and serum osteocalcin levels in postmenopausal women with idiopathic benign paroxysmal positional vertigo. Methods: A total of 64 postmenopausal women with idiopathic BPPV were selected as the study group, and 98 postmenopausal healthy women were selected as the control group. Bone mineral density and serum osteocalcin levels were analyzed and compared between the groups.χ(2) test was used for numeration data and t test was used for measurement data. Results: The prevalence of osteoporosis or osteopenia in BPPV group 67.2% (43/64) was significantly higher than that in the control group 51.0% (50/98) (χ(2)=4.139, P=0.042). Among BPPV subjects, there was a negative correlation between osteocalcin and bone density T (r=-0.469, P<0.001). Osteocalcin was found in normal bone mass subgroup (13.61±4.32)μg/L, decreased bone mass subgroup (17.49±7.61)μg/L, and osteoporosis subgroup (20.83±6.72)μg/L, respectively, and the difference was statistically significant (F=5.39, P=0.007). Conclusions: Bone mineral density in BPPV group is lower than that in control group. The lower the bone mineral density of the patients, the higher the osteocalcin in BPPV group.

[Prevalence and clinical characteristics of blood eosinophilia in patients with acute exacerbation of chronic obstructive pulmonary disease]

Objective: To investigate the prevalence and clinical characteristics of peripheral blood eosinophilia (EOS) in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Methods: From July 2014 to June 2016, AECOPD patients in the Department of Respiratory Medicine of Affiliated Hospital of Chengdu University, were retrospectively stratified into two groups according to two standards of eosinophilic exacerbations (the peripheral blood eosinophil count ≥2% or ≥3% on admission). Demography, clinical symptoms, laboratory results, length of stay, total hospitalization expenses, and defined daily expenses were compared between groups. Results: A total of 559 cases with AECOPD were finally recorded, the prevalence of eosinophilia was 43.1% (241 cases by EOS≥2%) and 27.2% (152 cases by EOS≥3%), respectively. According to either standard, there were no significant differences in sexes, age, course of disease (P>0.05), and there were no significant differences in global initiative for chronic obstructive lung disease (GOLD) grades, parameters of pulmonary function, modified british medical research council (mMRC) scores, rate of antibiotic use, systemic glucocorticoids administration, and average daily expenses (P>0.05). According to 2% standard, leucocytes, neutrophils, monocytes, hs-CRP were lower than non-eosinophilic patients [(5.9±2.0)×10(9)/L vs (8.2±4.0)×10(9)/L, (3.9±1.6)×10(9)/L vs (6.5±3.8)×10(9)/L, (0.446±0.169)×10(9)/L vs (0.501±0.276)×10(9)/L, (25.8±35.9) vs (46.2±55.6) mg/L, all P<0.01]; basophils, lymphocytes were higher than non-eosinophilic patients [(0.043±0.025)×10(9)/L vs (0.029±0.021) ×10(9)/L, (1.3±0.6) ×10(9)/L vs (1.1±0.6) ×10(9)/L, both P<0.01]; length of stay, total hospital expense were shorter (or lower) than non-eosinophilic patients [(10.6±5.0) vs (11.6±5.8) d, (11 851±7 491) vs (14 254±10 751) RMB, both P<0.05]. According to 3% standard, leucocytes, neutrophils, monocytes, hs-CRP were lower than non-eosinophilic patients (all P<0.05), and basophil were higher than non-eosinophilic patients (P<0.01), but no significant differences were observed in lymphocytes, length of stay and total hospital expense (all P>0.05). Conclusion: Eosinophilia is of relative high prevalence in AECOPD patients, and basophil in eosinophilic patients is higher than non-eosinophilic patients.

Repeated 2% sevoflurane administration in 7‑ and 60-day-old rats : Neurotoxicity and neurocognitive dysfunction

BACKGROUND

Sevoflurane is one of the most widely used inhalation anesthetics in pediatric anesthesia. A large number of studies have demonstrated that repeated treatment with high concentrations or long durations of sevoflurane anesthesia during the neonatal period can induce neuroapoptosis and long-term learning disability. In clinical practice, we observed that a subset of patients underwent minor surgery under sevoflurane anesthesia more than once from birth to adolescence. Therefore, this research was conducted to investigate whether a 2% concentration of sevoflurane (clinically relevant usage of sevoflurane) for 1 h (a short duration) can induce neuroapoptosis and neurocognitive dysfunction in adolescent rats that received sevoflurane (2% for 1 h) during the neonatal period.

MATERIAL AND METHODS

Group I: neonatal rats at postnatal day 7 (PND-7) were treated with oxygen under controlled conditions and then raised to PND-60. Group II: PND-7 rats were treated with 2% sevoflurane for 1 h and then raised to PND-60. Group III: the PND-60 rats were treated with 2% sevoflurane for 1 h and in group IV the PND-7 rats were treated with 2% sevoflurane for 1 h and then anesthetized with 2% sevoflurane for 1 h at PND-60 again. The expression of caspase-3, Bax and Bcl-2 in the hippocampal dentate gyrus (DG) were measured by Western blot analysis. Neuroapoptosis in the hippocampal DG was assessed using NeuN/caspase-3 double-immunofluorescence staining. Spatial reference memory was tested by the Morris water maze test.

RESULTS

The present data showed that sevoflurane (2% for 1 h) did not induce obvious hippocampal neuroapoptosis in the PND-7 rats and PND-60 rats; their performance in hippocampal-dependent spatial memory was not significantly impaired; however, the rats in group IV showed poor performance in the Morris water maze test and the neuroapoptosis in group IV was significantly increased.

CONCLUSION

Our findings suggested that sevoflurane can induce neuroapoptosis and cognitive dysfunction in adolescent rats that received repeated sevoflurane (2% for 1 h) during the postnatal period. These findings will promote further studies to investigate the effects of repeated sevoflurane exposure on the development of the central nervous system and function of learning and memory, as well as the underlying mechanisms in vitro and in vivo.

Fructose-1,6-bisphosphate and aldolase mediate glucose sensing by AMPK

The major energy source for most cells is glucose, from which ATP is generated via glycolysis and/or oxidative metabolism. Glucose deprivation activates AMP-activated protein kinase (AMPK), but it is unclear whether this activation occurs solely via changes in AMP or ADP, the classical activators of AMPK. Here, we describe an AMP/ADP-independent mechanism that triggers AMPK activation by sensing the absence of fructose-1,6-bisphosphate (FBP), with AMPK being progressively activated as extracellular glucose and intracellular FBP decrease. When unoccupied by FBP, aldolases promote the formation of a lysosomal complex containing at least v-ATPase, ragulator, axin, liver kinase B1 (LKB1) and AMPK, which has previously been shown to be required for AMPK activation. Knockdown of aldolases activates AMPK even in cells with abundant glucose, whereas the catalysis-defective D34S aldolase mutant, which still binds FBP, blocks AMPK activation. Cell-free reconstitution assays show that addition of FBP disrupts the association of axin and LKB1 with v-ATPase and ragulator. Importantly, in some cell types AMP/ATP and ADP/ATP ratios remain unchanged during acute glucose starvation, and intact AMP-binding sites on AMPK are not required for AMPK activation. These results establish that aldolase, as well as being a glycolytic enzyme, is a sensor of glucose availability that regulates AMPK.

[The correlation analysis of the cochlear hydrops degree found by MRI angiography with Meiniere's disease classification]

Objective:To investigate the correlation between the levels of cochlear hydrops with the clinic classification of Meniere's disease(MD).Method:3D-FlAIR MRI was performed 24 hours after intratympanic injection of 8-fold diluted Gadopentetate Dimeglumine in 31 patients with unilateral MD. We evaluated the levels of cochlear hydrops and further analyzed the correlation between the levels of cochlear hydrops and thresholds of pure tone audiometry and clinic classification of MD. Result:MRI image clearly distinguished perilymph from endolymph in the labyrinth. The images showed different levels of enhancement of perilymphatic fluid spaces. In the 31 patients, obvious signs of endolymphatic hydrops were found, including 4 cases of level 0, 6 cases of level 1, 11 cases of level 2 and 10 cases of level 3. Their average hearing threshold was(54.37±3.88)dB HL. The levels of cochlear hydrops were significantly correlated with pure tone audiometry thresholds （r=0.636，P<0.01） and MD classification(r=0.516,P<0.01). None of the patients after intratympanic injection complained about discomfort or happened with any complications such as eardrum perforation, infection, and so on. Conclusion:The degree of endolymphatic hydrops based on MRI in MD patient has significant correlation with the pure tone audiometry and classification of disease. The examination can act as an objective index for MD diagnosis.

Transcriptome analysis of molecular mechanisms responsible for light-stress response in Mythimna separata (Walker)

Light is an important environmental signal for most insects. The Oriental Armyworm, Mythimna separata, is a serious pest of cereal crops worldwide, and is highly sensitive to light signals during its developmental and reproductive stages. However, molecular biological studies of its response to light stress are scarce, and related genomic information is not available. In this study, we sequenced and de novo assembled the transcriptomes of M. separata exposed to four different light conditions: dark, white light (WL), UV light (UVL) and yellow light (YL). A total of 46,327 unigenes with an average size of 571 base pairs (bp) were obtained, among which 24,344 (52.55%) matched to public databases. The numbers of genes differentially expressed between dark vs WL, dark vs UVL, dark vs YL, and UVL vs YL were 12,012, 12,950, 14,855, and 13,504, respectively. These results suggest that light exposure altered gene expression patterns in M. separata. Putative genes involved in phototransduction-fly, phototransduction, circadian rhythm-fly, olfactory transduction, and taste transduction were identified. This study thus identified a series of candidate genes and pathways potentially related to light stress in M. separata.

Urotensin II inhibitor eases neuropathic pain by suppressing the JNK/NF-κB pathway

Urotensin II (U-II), a cyclic peptide originally isolated from the caudal neurosecretory system of fishes, can produce proinflammatory effects through its specific G protein-coupled receptor, GPR14. Neuropathic pain, a devastating disease, is related to excessive inflammation in the spinal dorsal horn. However, the relationship between U-II and neuropathic pain has not been reported. This study was designed to investigate the effect of U-II antagonist on neuropathic pain and to understand the associated mechanisms. We reported that U-II and its receptor GPR14 were persistently upregulated and activated in the dorsal horn of L4-6 spinal cord segments after chronic constriction injury (CCI) in rats. Intrathecal injection of SB657510, a specific antagonist against U-II, reversed CCI-induced thermal hyperalgesia and mechanical allodynia. Furthermore, we found that SB657510 reduced the expression of phosphorylated c-Jun N-terminal kinase (p-JNK) and nuclear factor-κB (NF-κB) p65 as well as subsequent secretion of interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α). It was also showed that both the JNK inhibitor SP600125 and the NF-κB inhibitor PDTC significantly attenuated thermal hyperalgesia and mechanical allodynia in CCI rats. Our present research showed that U-II receptor antagonist alleviated neuropathic pain possibly through the suppression of the JNK/NF-κB pathway in CCI rats, which will contribute to the better understanding of function of U-II and pathogenesis of neuropathic pain.

Interleukin-6 and interleukin-8 in diagnosing neonatal septicemia

Neonatal septicemia (NS) is a common cause of death of newborn infants, hence early diagnosis and treatment are of the utmost importance. However, lack of specific clinical symptoms and late detection delay a correct diagnosis. It is therefore of great importance to establish auxiliary indexes for the early diagnosis of NS. To evaluate the value of interleukin (IL-6 and IL-8) in the diagnosis of NS, a prospective study was carried out. Seventy-five newborns who developed septicemia and received treatment in our hospital from January 2013 to December 2014 were selected as research subjects; also, 50 healthy newborns were set as a control group. The levels of serum IL-6 and IL-8 were compared between the two groups. Results demonstrated that levels of C-reactive protein (CRP), IL-6 and IL-8 of the septicemia group were higher than those of the control group on admission, although the difference had no statistical significance (P less than 0.05); the septicemia group had higher sequential organ failure assessment (SOFA) scores but lower pediatric critical illness scores (PCIS) compared to the control group (P less than 0.05); levels of CRP, IL-6 and IL-8 were in positive correlation to the SOFA scores and in negative correlation to PCIS. Analysis of receiver operating characteristics (ROC) curve demonstrated that the sensitivity, specificity and accuracy were 85.7%, 80.2% and 81.8%, respectively, when IL-6 level was set as 32 pg/mL, 78.1%, 64.2% and 66.9%, respectively when IL-8 level was set as 54 pg/mL, and 71.4%, 86.3% and 82.7% respectively, when detection of IL-6 and IL-8 were combined together. Hence it can be concluded that: IL-6 and IL-8 are involved in inflammatory reactions; levels of IL-6 and IL-8 were correlated to the severity of the infection; the value of IL-6 is higher than that of IL-8 in the diagnosis of neonatal septicemia and the combined detection of IL-6 and IL-8 can improve the accuracy of the diagnosis of neonatal septicemia.

[Treatment of isolated sphenoid sinus disease by trans-basal lamella approach to sphenoid sinus]

Objective:The aim of this study is to investigate the safety and practicability of the trans-horizontal basal lamella sphenoidotomy approach in the treatment of the isolated sphenoid sinus disease.Method:Sphenoidotomy and posterior-ethmoidotomy by endoscopic trans-horizontal basal lamella approach were performed in 64 patients who were diagnosed with isolated sphenoid sinus.The horizontal course of the basal lamella is perforated and opened,and the superior meatus is entered.Then sphenoidotomy and posterior-ethmoidotomy were performed by the landmark superior turbinate.Result:All patients were successfully operated without serious complications.After 1 year follow-up,no recurrence were found in 30 cases of fungal sphenoid sinusitis patients,12 cases of chronic sphenoidal sinusitis patients,13 cases of sphenoid sinus cyst patients,6 cases of sphenoid sinus polyps patients,and 3 cases of sphenoid sinus inverted papilloma patients.The ostium of sphenoid sinus maintained well without atresia.Conclusion:Trans-horizontal basal lamella approach to sphenoid sinus is safe and effective in the treatment of isolated lesion,and the opening of sphenoid sinus and posterior-ethmoid sinus were enlarged better by this technique.

The genetic diversity of SMLS (Sitobion miscanthi L type symbiont) and its effect on the fitness, mitochondrial DNA diversity and Buchnera aphidicola dynamic of wheat aphid, Sitobion miscanthi (Hemiptera: Aphididae)

SMLS (Sitobion miscanthi L type symbiont) is a recently discovered aphid secondary symbiont. Using evidence extracted from 16S rRNA sequences, previous studies indicate that SMLS is the most widely distributed and most recently transferred secondary symbiont in Chinese Sitobion miscanthi populations. Here, we further investigated genetic diversity among SMLS geographic strains with multiloci data. Furthermore, the influence of SMLS on S. miscanthi was uncovered with ecological and evolutionary evidence. The results indicated that there was limited influence of infection with SMLS on variation and evolutionary patterns of S. miscanthi mitochondrial DNA. By hemolymph injection, the SMLS-infected and SMLS-uninfected S. miscanthi clones with the identical genetic background were built in this study. Although similar Buchnera aphidicola dynamics were observed between SMLS-infected and SMLS-uninfected S. miscanthi population, B. aphidicola density of SMLS-infected S. miscanthi population was always significantly higher than SMLS-uninfected ones. The results of fitness measurements indicated that under laboratory rearing conditions, transfection of SMLS could confer modest advantages to some fitness components of S. miscanthi, that is, total number of offspring, longevity, age of first reproduction and weight of adult. However, as SMLS is not strictly associated with S. miscanthi, further investigations are needed to uncover the mechanisms responsible for this inconceivable association.

Ketamine Affects the Neurogenesis of the Hippocampal Dentate Gyrus in 7-Day-Old Rats

Ketamine has been reported to cause neonatal neurotoxicity via a neuronal apoptosis mechanism; however, no in vivo research has reported whether ketamine could affect postnatal neurogenesis in the hippocampal dentate gyrus (DG). A growing number of experiments suggest that postnatal hippocampal neurogenesis is the foundation of maintaining normal hippocampus function into adulthood. Therefore, this study investigated the effect of ketamine on hippocampal neurogenesis. Male Sprague-Dawley rats were divided into two groups: the control group (equal volume of normal saline), and the ketamine-anesthesia group (40 mg/kg ketamine in four injections at 1 h intervals). The S-phase marker 5-bromodeoxyuridine (BrdU) was administered after ketamine exposure to postnatal day 7 (PND-7) rats, and the neurogenesis in the hippocampal DG was assessed using single- or double-immunofluorescence staining. The expression of GFAP in the hippocampal DG was measured by western blot analysis. Spatial reference memory was tested by Morris water maze at 2 months after PND-7 rats exposed to ketamine treatment. The present results showed that neonatal ketamine exposure significantly inhibited neural stem cell (NSC) proliferation, decreased astrocytic differentiation, and markedly enhanced neuronal differentiation. The disruptive effect of ketamine on the proliferation and differentiation of NSCs lasted at least 1 week and disappeared by 2 weeks after ketamine exposure. Moreover, the migration of newborn neurons in the granule cell layer and the growth of astrocytes in the hippocampal DG were inhibited by ketamine on PND-37 and PND-44. Finally, ketamine caused a deficit in hippocampal-dependent spatial reference memory tasks at 2 months old. Our results suggested that ketamine may interfere with hippocampal neurogenesis and long-term neurocognitive function in PND-7 rats. These findings may provide a new perspective to explain the adult neurocognitive dysfunction induced by neonatal ketamine exposure.

Geometrical and morphological optimizations of plasmonic nanoarrays for high-performance SERS detection

Here we present an in-depth and comprehensive study of the effect of the geometry and morphology of nanoarray (NA) substrates on their surface-enhanced Raman scattering (SERS) performance. The high-quality SERS-active NA substrates of various unit shapes and pitches are assembled through electron beam lithography and fabricated by electron beam physical vapor deposition. Good agreement is found on comparing the Raman scattering results with the integrals of the fourth power of local electric fields from the three-dimensional numerical simulations. A novel type of hybrid NA substrate composed of disordered nanoparticles and a periodic NA is fabricated and characterized. The morphology of NAs has little influence on the SERS performance of hybrid NA substrates and they perform better than both their counterparts pure NA and disordered nanoparticle substrates.

Propofol Inhibits Lipopolysaccharide-Induced Inflammatory Responses in Spinal Astrocytes via the Toll-Like Receptor 4/MyD88-Dependent Nuclear Factor-κB, Extracellular Signal-Regulated Protein Kinases1/2, and p38 Mitogen-Activated Protein Kinase Pathways

BACKGROUND

In this study, we investigated the effect of propofol, a commonly used IV anesthetic, on lipopolysaccharide (LPS)-induced inflammatory responses in astrocytes and explored the molecular mechanisms by which it occurs.

METHODS

Astrocytes were stimulated with LPS (1.0 μg/mL) in the absence and presence of different concentrations of propofol. The expression of astrocyte marker glial fibrillary acidic protein (GFAP) in astrocytes was detected using immunofluorescence staining and Western blot analysis. The levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor-α were measured using an enzyme-linked immunosorbent assay. The mRNA level of Toll-like receptor 4 (TLR4) was determined by semiquantitative reverse transcriptase-polymerase chain reaction. The protein expressions of TLR4, myeloid differentiation factor 88 (MyD88), p- extracellular signal-regulated protein kinases (ERK)1/2, p-c-Jun N-terminal kinase, p-p38 mitogen-activated protein kinase (MAPK), p-I-κBα, I-κBα, and p-nuclear factor-κB (NF-κB)p65 were detected by Western blot.

RESULTS

Our results show that after stimulation with LPS, the levels of IL-1β, IL-6, and tumor necrosis factor-α and the expression of GFAP in astrocytes were up-regulated significantly. In addition, the expression of TLR4, MyD88, p-ERK1/2, p-c-Jun N-terminal kinase, p-p38 MAPK, and p-NF-κBp65 increased, whereas the expression of total I-κBα decreased upon stimulation with LPS. Propofol (10 μM) reduced the secretion of proinflammatory cytokines, inhibited the expressions of GFAP, TLR4, MyD88, p-ERK1/2, p-p38 MAPK, and p-NF-κBp65 in astrocytes challenged with LPS.

CONCLUSIONS

In the present study, propofol 10 μM but not lower clinically relevant or higher supra-clinical concentrations attenuated LPS-induced astrocyte activation and subsequent inflammatory responses by inhibiting the TLR4/MyD88-dependent NF-κB, ERK1/2, and p38 MAPK pathways.

Dexmedetomidine prevents post-ischemic LTP via presynaptic and postsynaptic mechanisms

Increasing evidence indicates that dexmedetomidine (DEX), a selective α2-adrenergic receptor agonist, has a neuroprotective effect against cerebral injury. However, it remains unknown whether and how DEX functionally prevents the pathological form of synaptic plasticity caused by ischemia in the hippocampal CA1 neurons. To address this issue, we analyzed the role of DEX using a model of brain ischemia (oxygen and glucose deprivation, OGD) referred to as post-ischemic LTP (i-LTP). We found that DEX could reduce i-LTP by selectively activating α2 receptors. To clarify its detailed mechanisms, the presynaptic and postsynaptic roles of DEX were investigated. The activation of the α2 receptors of DEX decreased the frequency spontaneous mEPSCs, which exerted its presynaptic mechanisms. In addition, DEX also decreased the amplitude of mEPSCs and prevented the depolarization of postsynaptic membranes during OGD treatment, which exerted its postsynaptic mechanisms. More importantly, our results indicate that postsynaptic β receptors, not α1 receptors, participated in i-LTP. Therefore, these results demonstrated that decreasing β receptors activation by DEX-medicated pre- and post-synaptic α2 receptors activation is responsible for i-LTP. Because of the NMDARs required for i-LTP, we further examined the critical roles of postsynaptic β receptors downstream PKA regulation of NMDA receptor-mediated EPSCs (NMDA EPSC). We clarified that it is attributable to the direct effect of DEX on NMDA EPSC as mediated by PKA inactivation. These findings suggest that DEX can protect neurons from functional damage caused by a relatively mild degree of transient cerebral ischemia, and this effect is mediated by both presynaptic reduction of NE and glutamate release and postsynaptic suppression of NMDAR activation by β receptors and downstream PKA regulation.

Ketamine interferes with the proliferation and differentiation of neural stem cells in the subventricular zone of neonatal rats

BACKGROUND

Previous studies have shown ketamine can alter the proliferation and differentiation of neural stem cells (NSCs) in vitro. However, these effects have not been entirely clarified in vivo in the subventricular zone (SVZ) of neonatal rats. The present study was designed to investigate the effects of ketamine on the proliferation and differentiation of NSCs in the SVZ of neonatal rats in vivo.

METHODS

Postnatal day 7 (PND-7) male Sprague-Dawley rats were administered four injections of 40 mg/kg ketamine at 1-h intervals, and then 5-bromodeoxyuridine (BrdU) was injected intraperitoneally at PND-7, 9 and 13. NSC proliferation was assessed with Nestin/BrdU double-labeling immunostaining. Neuronal and astrocytic differentiation was evaluated with β-tubulin III/BrdU and GFAP/BrdU double-labeling immunostaining, respectively. The expressions of nestin, β-tubulin III and GFAP were measured using Western blot analysis. The apoptosis of NSCs and astrocytes in the SVZ of neonatal rats was evaluated using nestin/caspase-3 and GFAP/caspase-3 double-labeling immunostaining.

RESULTS

Neonatal ketamine exposure significantly reduced the number of nestin/BrdU and GFAP/BrdU double-positive cells in the SVZ. Meanwhile, the expressions of nestin and GFAP in the SVZ from the ketamine group were significantly decreased compared those in the control group. Still, no double-positive cells for nestin/caspase-3 and GFAP/caspase-3 were found after ketamine exposure. In addition, the neuronal differentiation of NSCs in the SVZ was markedly promoted by ketamine with an increased number of β-tubulin III/BrdU double-positive cells and enhanced expression of β-tubulin III. These effects of ketamine on the NSCs in the SVZ often lasted at least 1 week after ketamine anesthesia.

CONCLUSION

In the present study, it was demonstrated that ketamine could alter neurogenesis by inhibiting the proliferation of NSCs, suppressing their differentiation into astrocytes and promoting the neuronal differentiation of the NSCs in the SVZ of neonatal rats during a critical period of their neurodevelopment.

Prevalence and genotyping of Toxoplasma gondii in naturally-infected synanthropic rats (Rattus norvegicus) and mice (Mus musculus) in eastern China

Background

Synanthropic rats and mice share the same environment with humans and play an important role in epidemiology of toxoplasmosis; however, there is limited information about prevalence and genetic characterization of Toxoplasma gondii in synanthropic rats and mice in China.

Findings

In the present study, the prevalence and genetic characterization of T. gondii naturally infected synanthropic rodents (Rattus norvegicus and Mus musculus) were investigated in the urban area of Xuzhou city, Eastern China between June 2013 and August 2014. DNA from the brain of each animal was prepared and screened by specific PCR assay targeting 35-fold repeated B1 gene (B1-PCR). PCR positive DNA samples were further genotyped by multi-locus PCR-RFLP. Overall, out of 123 synanthropic rodents, 29 samples were positive by B1 gene-targeted PCR (23.6%). Of these, 7 out of 31 (22.3%) M. musculus were positive, whereas the positive rate of R. norvegicus was 23.9% (22/92). Multi-locus PCR-RFLP analysis reveals that seven PCR-positive samples were completely genotyped and they were identified as type China 1 (ToxoDB# 9).

Conclusion

To our knowledge, this is the first report of molecular detection and genetic characterization of T. gondii infection in synanthropic rodents in Eastern China. The results of the present study showed a high infection pressure of T. gondii exists in the environment and synanthropic rodents infected by T. gondii may be an important source of infection for cats and other animals.

Ketamine inhibits proliferation of neural stem cell from neonatal rat hippocampus in vitro

BACKGROUND/AIMS

Ketamine is a widely used anesthetic in obstetric and pediatric anesthesia. In the developing brain, the widespread neuron apoptosis triggered by ketamine has been demonstrated. However, little is known about its effect on neural stem cells (NSCs) function. This study aimed to investigate the effect of ketamine on proliferation of NSCs from neonatal rat hippocampus.

METHODS

Neural stem cells were isolated from the hippocampus of Sprague-Dawley rats on postnatal day 3. In dose-response experiments, cultured neural stem cells (NSCs) were exposed to different concentrations of ketamine (0-1000 µM) for 24 hrs. The proliferative activity of NSCs was evaluated by 5-Bromo-2'-deoxyuridine (BrdU) incorporation assay. Apoptosis of neural stem cells were assessed using caspase-3 by western blot. The intracellular Ca(2+) concentration ([Ca(2+)]i) in NSCs was analyzed by flow cytometry. The activation of protein kinase C-α (PKCα) and the phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2) were measured by western blot analysis.

RESULTS

Clinical relevant concentration of ketamine (10, 20 and 50 µM) did not markedly alter the proliferation of NSCs from neonatal rat hippocampus in vitro. However, ketamine (200, 500, 800 and 1000μM) significantly inhibited the proliferation of NSCs and did not affect the expression of caspase-3. Meanwhile, ketamine (200, 500, 800 and 1000μM) also markedly decreased [Ca(2+)]i as well as suppressed PKCα activation and ERK1/2 phosphorylation in NSCs. A combination of subthreshold concentrations of ketamine (100 μM) and Ca(2+) channel blocker verapamil (2.5 μM), PKCα inhibitor chelerythrine (2.5 μM) or ERK1/2 kinase inhibitor PD98059 (5 μM) significantly produced suprathreshold effects on PKCα activation, ERK1/2 phosphorylation and NSC proliferation.

CONCLUSION

Ketamine inhibited proliferation of NSCs from neonatal rat hippocampus in vitro. Suppressing Ca(2+)-PKCα-ERK1/2 signaling pathway may be involved in this inhibitory effect of ketamine on NSCs proliferation.

Diversity of bacterial symbionts in populations of Sitobion miscanthi (Hemiptera: Aphididae) in China

Aphids are a group of insects frequently associated with bacterial symbionts. Although Chinese aphids harbor a high level of species diversity, the associations between Chinese aphids and bacterial symbionts are less known. In this study, we uncovered the diversity of bacterial symbionts in a Chinese widespread aphid, Sitobion miscanthi (Takahashi). In this study, we detected the aphid obligate symbiont Buchnera aphidicola, and two secondary symbionts, Hamiltonella defensa and Regiella insecticola, with the diagnostic polymerase chain reaction method in S. miscanthi samples. In addition, symbiotic species of Acinetobacter, Aeromonas, Enterobacter, Pantoea, and Pseudomonas, and the family Enterobacteriaceae were also found. Geographically, sporadic occurrences were detected for H. defensa and R. insecticola. Moreover, the infection rates of them vary widely among the infected populations: H. defensa (5.26-95.2%) and R. insecticola (5.26-46.7%). Phylogenetic analyses indicated that the strain of B. aphidicola mirrored the history and divergence of S. miscanthi; however, the H. defensa and R. insecticola strains were probably experienced horizontal transmission among S. miscanthi and its distantly related species.

Salusin-β not salusin-α promotes vascular inflammation in ApoE-deficient mice via the I-κBα/NF-κB pathway

Objective

Vascular inflammation plays an important role in the development and progression of atherosclerosis. Recently, salusins (salusin-α and salusin-β) have been reported to be associated wtih atherosclerosis. However, its underlying mechanism remains incompletely known. In this study, we observed the effects of salusins on vascular inflammation in apoE-deficient (apoE-/-) mice.

Methods and Results

Six-week old male apoE-/- mice were infused with salusin-α, salusin-β or vehicle for 8 weeks via osmotic mini-pumps. Our results showed that apoE-/- mice receiving vehicle alone developed severe atherosclerotic lesions and dyslipidemia, with significantly up-regulated levels of IL-6, TNF-α, VCAM-1 and MCP-1. For apoE-/- mice receiving 8 weeks of salusin-β infusion, the atherosclerotic lesions were markedly aggravated, and the levels of IL-6, TNF-α, VCAM-1 and MCP-1 were substantially increased, despite a similar plasma lipid concentration with that of apoE-/- mice. However, after 8 week-infusion of salusin-α, apoE-/- mice presented significant amelioration in atherosclerotic lesions, along with remarkably up-regulated level of high-density lipoprotein-cholesterol (HDL-C) and down-regulated levels of IL-6 and TNF-α, but without any effect on the expressions of VCAM-1 and MCP-1. Furthermore, the activation of nuclear factor-κB (NF-κB), an important transcription factor essential for inflammatory molecules, and the degradation of I-κBα, an inhibitor of NF-κB, were markedly increased in apoE-/- mice receiving vehicle alone. Treatment with salusin-β not salusin-α could remarkably accelerate the process of NF-κB nuclear translocation and I-κBα degradation.

Conclusion

Salusin-β, but not salusin-α, promotes vascular inflammation in apoE-deficient mice via the I-κBα/NF-κB pathway. These findings provide further insight into the mechanism of salusins in atherosclerosis and potential targets for the prevention and treatment of atherosclerosis.