查找使用阿拉丁产品的科研文献

α-Asarone Alleviated Chronic Constriction Injury–Induced Neuropathic Pain Through Inhibition of Spinal Endoplasmic Reticulum Stress in an Liver X Receptor–Dependent Manner

Gui Yulong,Li Aiyuan,Zhang Jie,Li Guan,Ruan Xia,Guo Qulian,Zou Wangyuan

BACKGROUND: Neuropathic pain is an intractable and complex disease. Recent studies have shown a close relationship between endoplasmic reticulum (ER) stress and neuropathic pain. Here, we investigated the effect of α-asarone, an ER stress inhibitor, on chronic constriction injury (CCI)–induced neuropathic pain. METHODS: Two parts were included in this study. In part 1, rats were assigned to 7 groups: the sham group, the sham + α-asarone 20 mg/kg group, the CCI group, the CCI + vehicle group, the CCI + α-asarone 5 mg/kg group, the CCI + α-asarone 10 mg/kg group, and the CCI + α-asarone 20 mg/kg group. After surgery, the rats were treated with α-asarone or normal saline daily. Pain thresholds were measured, and samples of the L3–6 spinal cord were taken for western blotting and immunofluorescence on day 7. In part 2, rats were intrathecally implanted with PE-10 tubes and divided into 4 groups: the CCI + α-asarone 20 mg/kg group, the CCI + α-asarone 20 mg/kg + vehicle group, the CCI + α-asarone 20 mg/kg + SR9243 group, and the CCI group. Five rats in each group were separated for behavioral tests 1 hour after intrathecal injection. The rest of them were killed for western blotting on day 7. RESULTS: In this study, CCI surgery significantly induced mechanical allodynia and thermal hyperalgesia. CCI surgery significantly induced activation of ER stress (PERK-eIF2α, IRE1α, CHOP, and XBP-1s) in rats. However, treatment with 20 mg/kg of α-asarone significantly alleviated CCI-induced activation of ER stress. Behavioral results showed that daily treatment with 20 mg/kg of α-asarone significantly alleviated CCI-induced nociceptive behaviors, on day 7 (mechanical allodynia, P = .016, 95% confidence interval, 0.645–5.811; thermal hyperalgesia, P = .012, 95% confidence interval, 0.860–6.507). Furthermore, α-asarone induced upregulated expression of liver X receptor β (LXRβ) and downstream proteins in the spinal cord. The LXR antagonist SR9243 completely inhibited the anti-ER stress and antinociceptive effects of α-asarone in rats. CONCLUSIONS: α-Asarone relieved CCI-induced neuropathic pain in an LXR-dependent manner. α-Asarone may be a potential agent for treatment of neuropathic pain.

Large scale selective synthesis of α-Co(OH)2 and β-Co(OH)2 nanosheets through a fluoride ions mediated phase transformation process

Hongtao Cui,Yunan Zhao,Wanzhong Ren,Minmin Wang,Yan Liu

In this work, α-Co(OH) 2 and β-Co(OH) 2 nanosheets were selectively synthesized through an epoxide precipitation reaction under mediation of fluoride ions. The protonation and ring opening reaction of propylene oxide promoted the hydrolysis [Co(H 2 O) 6 ] 2+ to form a mixed phase of α-Co(OH) 2 and Co 2 (OH) 3 Cl in the condition of no existence of fluoride ions. Due to the enhanced hydrolysis of [Co(H 2 O) 6 ] 2+ under function of fluoride ions, pure phases of α-Co(OH) 2 and β-Co(OH) 2 were formed respectively at different concentration of fluoride ions. The mild reaction condition of this route allows for large scale synthesis of cobalt hydroxide nanosheets, which is only limited by volume of the vessel used as reactor.

Clematichinenoside inhibits VCAM-1 and ICAM-1 expression in TNF-α-treated endothelial cells via NADPH oxidase-dependent IκB kinase/NF-κB pathway

Simin Yan,Xu Zhang,Haili Zheng,Danhong Hu,Yongtian Zhang,Qinghua Guan,Lifang Liu,Qilong Ding,Yunman Li

Proinflammatory cytokine TNF-α-induced adhesion of leukocytes to endothelial cells plays a critical role in the early stage of atherosclerosis . Oxidative stress and redox-sensitive transcription factors are implicated in the process. Thus, compounds that mediate intracellular redox status and regulate transcription factors are of great therapeutic interest. Clematichinenoside (AR), a triterpene saponin isolated from the root of Clematis chinensis Osbeck , was previously demonstrated to have anti-inflammatory and antioxidative properties. However, little is known about the exact mechanism underlying these actions. Thus we performed a detailed study on its effect on leukocytes–endothelial cells adhesion with TNF-α-stimulated human umbilical vein endothelial cells (HUVECs) and cell-free systems. First, we found that AR reduced TNF-α-induced VCAM-1 and ICAM-1 expression and their promoter activity, inhibited translocation of p65 and phosphorylation of IκBα , suppressed IκB kinase-β (IKK-β) activity, lowered O 2 ∙− and H 2 O 2 levels, tackled p47 phox translocation, and decreased NOX4 NADPH oxidase expression. Second, we showed that AR exhibited no direct free radical scavenging ability in cell-free systems at concentrations that were used in intact cells. Besides, AR had no direct effect on the activity of IKK-β that was extracted from TNF-α-stimulated HUVECs. We also found that p47 translocation, NOX4 expression, and reactive oxygen species (ROS) levels were up-regulated before IκB phosphorylation in TNF-α-induced HUVECs. Moreover, TNF-α-enhanced IKK-β activity was also inhibited by (polyethylene glycol) PEG–catalase, N -acetylcysteine (NAC), and vitamin E. In conclusion, these results suggest that AR reduces VCAM-1 and ICAM-1 expression through NADPH oxidase-dependent IKK/NF-κB pathways in TNF-α-induced HUVECs, which finally suppress monocyte–HUVECs adhesion. This compound is potentially beneficial for early-stage atherosclerosis.

Paramecium-like α-MnO2 hierarchical hollow structures with enhanced electrochemical capacitance prepared by a facile dopamine carbon-source assisted shell-swelling etching method

Zhiwei Wen,Wen She,Yuesheng Li,Renchao Che

Enhancement of the electrochemical performances of electrode materials is a great challenge in the electrochemical capacitor field. Herein, a novel paramecium-like α-MnO2 hierarchical hollow structure used as an electrode material has been successfully prepared, which possesses an ultra-high specific surface area (285 m2 g−1), uniform crystal orientation, and high specific capacitance (554.3 F g−1 at 1 A g−1) and exhibits 97.9% capacitance retention after 5000 cycles. The earlier carbonaceous coating transformed from dopamine plays an important role in forming this novel paramecium-like morphology. The shells are constructed of ultra-thin α-MnO2 nanoflakes with highly uniform and preferentially exposed [001] crystal orientation. The high specific surface area increases the electrolyte–electrode contact area and the unique orientated structure effectively facilitates ion transportation. Quasi in situ electron energy-loss spectroscopy (EELS) analysis for both hierarchical hollow structures and commercial products at different charge–discharge stages indicates that Mn in our products can be almost completely restored to its original oxidation valence state due to a complete redox reaction, while there is still a fraction of Mn in the commercial product that cannot be restored, which causes the reduction of specific capacitance and retention. All the results suggest that this novel α-MnO2 hierarchical hollow structure with selective growth orientation might become an attractive type of electrode material.

Enhancing the intestinal absorption of low molecular weight chondroitin sulfate by conjugation with α-linolenic acid and the transport mechanism of the conjugates

Yuliang Xiao,Pingli Li,Yanna Cheng,Xinke Zhang,Juzheng Sheng,Decai Wang,Juan Li,Qian Zhang,Chuanqing Zhong,Rui Cao,Fengshan Wang

The purpose of this report was to demonstrate the effect of amphiphilic polysaccharides-based self-assembling micelles on enhancing the oral absorption of low molecular weight chondroitin sulfate (LMCS) in vitro and in vivo , and identify the transepithelial transport mechanism of LMCS micelles across the intestinal barrier. α-Linolenic acid-low molecular weight chondroitin sulfate polymers(α-LNA–LMCS) were successfully synthesized, and characterized by FTIR, 1 HNMR, TGA/DSC, TEM, laser light scattering and zeta potential . The significant oral absorption enhancement and elimination half-life ( t 1/2 ) extension of LNA–LMCS2 in rats were evidenced by intragastric administration in comparison with CS and LMCS. Caco-2 transport studies demonstrated that the apparent permeability coefficient ( P app ) of LNA–LMCS2 was significantly higher than that of CS and LMCS ( p   <   0.001), and no significant effects on the overall integrity of the monolayer were observed during the transport process. In addition, α-LNA–LMCS micelles accumulated around the cell membrane and intercellular space observed by confocal laser scanning microscope (CLSM). Furthermore, evident alterations in the F-actin cytoskeleton were detected by CLSM observation following the treatment of the cell monolayers with α-LNA–LMCS micelles, which further certified the capacity of α-LNA–LMCS micelles to open the intercellular tight junctions rather than disrupt the overall integrity of the monolayer. Therefore, LNA–LMCS2 with low cytotoxicity and high bioavailability might be a promising substitute for CS in clinical use, such as treating osteoarthritis , atherosclerosis , etc.

An electrochemiluminescence sensing for DNA glycosylase assay with enhanced host-guest recognition technique based on α-cyclodextrin functionalized gold/silica cell-shell nanoparticles

Tingting Zhang,Huimin Zhao,Xie Quan,Shuo Chen

An electrochemiluminescence (ECL) sensing for sensitive assaying of active DNA glycosylase was developed using the enhanced host-guest recognition technique. The α-cyclodextrin was selected as the host molecule which captured the guest-labeled ECL probe to the surface of electrode by the host-guest recognition. The ECL probe can be protected from the digestion of exonuclease I (Exo I) and exonuclease III (Exo III) with the presence of the target enzyme human 8-oxoguanine DNA glycosylase 1 (hOGG 1), resulting in the ECL emission intensity was correlated with the quantity of hOGG 1. The α-cyclodextrin functionalized gold/silica (Au/SiO 2 ) cell-shell nanoparticles was prepared to enhance the host-guest recognition sensitivity. Because of the increased recognition sites provided by α-cyclodextrin functionalized Au/SiO 2 cell-shell nanoparticles, the nanoparticle-modified electrode displayed a high capacity for the guest ECL probe, and four fold enhancement of the ECL signals was achieved. The as-prepared ECL sensing exhibits excellent analytical property for the detection of hOGG 1 in the linear range of 2–100 U mL −1 with a detection limit of 0.225 U mL −1 (S/N   =   3). Interference tests show that the ECL intensity of the interferents human apurinic/apyrimidinic endonuclease (APE 1), T4 endonuclease V (T4 PDG) and endonuclease III (Endo III) is within 36.5 to 44.7% of that of hOGG 1. The ECL sensing exhibits long-term stability with a relative standard deviation (RSD) of 1.6% for 16 cycles of continuous potential scans, and the life time of the ECL sensing is up to 20 days. The obtained results in this study indicate that the proposed ECL sensing possesses high sensitivity, specificity and stability and provides a powerful tool for assaying hOGG 1 activity.

A sandwich-type electrochemical immunosensor based on multiple signal amplification for α-fetoprotein labeled by platinum hybrid multiwalled carbon nanotubes adhered copper oxide

Liping Jiang,Jian Han,Faying Li,Jian Gao,Yueyun Li,Yunhui Dong,Qin Wei

In this work, we designed a novel and ultrasensitive sandwich-type electrochemical immunosensor for quantitative detection of α-fetoprotein (AFP), using β-cyclodextrin functionalized graphene (CD-GS) as the platform and platinum hybrid multiwalled carbon nanotubes adhered copper oxide (Pt@CuO-MWCNTs) as labels. CD-GS has high specific surface area, ideal dispersibility and good biocompatibility, which was used to efficiently capture more primary antibodies (Ab 1 ). Pt, CuO and multiwalled carbon nanotubes (MWCNTs) can be used as catalysts for the decomposition of hydrogen peroxide. The Pt@CuO-MWCNTs realized multiple amplified signals due to their synergy. Therefore, Pt@CuO-MWCNTs was used as the marker, combined with secondary antibodies (Ab 2 ) and this has the effect of multiple amplified signals to catalyze hydrogen peroxide. Under optimal conditions the designed immunosensor exhibited a wide linear range from 1   pg   mL −1 to 20   ng   mL −1 with a low detection limit of 0.33   pg   mL −1 (S/N   =   3) for AFP. The designed immunosensor showed good selectivity, reproducibility and stability, which could provide potential applications in clinical monitoring of AFP.

Exploring the effect of bisphenol S on sludge hydrolysis and mechanism of the interaction between bisphenol S and α-Amylase through spectrophotometric methods

Hang Yang,Guangying Hou,Li Zhang,Lei Ju,Chunguang Liu

Sewage sludge , as a very significant sources of BPS (up to 523   mg/kg dw) introduction into the environment, must be handled properly. Therefore, it is important to access BPS removal and its effect on sludge treatment with the biological treatment. However, it is unclear for its effect on the hydrolysis of sludge. In this research, impact of BPS on sludge hydrolysis by α-Amylase is studied from the respect of component of soluble organic matter in sludge using three-dimensional fluorescence spectra . Enzyme activity assay suggests that sludge hydrolysis is inhibited due to the denaturation of α-Amylase with BPS exposure. In order to illuminate the interaction mechanism between BPS and α-Amylase, UV–vis, steady-state fluorescence, circular dichroism , synchronous fluorescence, light scattering spectra, enzyme activity assay and molecule docking techniques are applied. Results show that BPS interacts with α-Amylase by hydrophobic bond in the activity region of α-Amylase. This interaction not only causes an unfolding skeleton structure of α-Amylase and a less hydrophobic microenvironment of tyrosine and tryptophan residues, but also leads to a specific fluorophore quenching involving static and dynamic type. This work provides direct evidence about enzyme toxicity of BPS and establishes a new strategy to investigate the interaction between protein and BPS at a molecular level, which is helpful for clarifying the bioactivities of BPS.

Solubility of α-glycine in water with additives at a temperature range of (293.15–343.15) K: Experimental data and results of thermodynamic modeling

Hua Sun,Lu Wang,Baoshu Liu

The solubility of α-glycine in water with different additives (sodium nitrate, ammonium nitrate , ammonium sulfate , and ammonium chloride) was measured under atmospheric pressure across the temperature range of (293.15–343.15) K at intervals of 10.00 K using a dynamic laser method. Solubility was found to increase with increasing temperature and additive level. The experimental data were correlated with the modified Apelblat model, nonrandom two-liquid model (NRTL), and λh model. The R 2 of the fitting regression indicated good applicability of these models to the glycine solubility data in the studied systems ( R 2  > 0.99). Apparent standard enthalpy, entropy, and Gibbs free energy changes of the solution were calculated based on the van't Hoff equation to elucidate the dissolution mechanism. The results showed that the dissolving process of glycine was endothermic, and the main dissolution driving force contributor was enthalpy in all the additive + water systems studied. By means of enthalpy-entropy compensation analysis, a non linear Δ H sol Θ versus Δ G sol Θ enthalpy-entropy compensation plot with positive and negative slopes was obtained for the systems studied. The evaluated values of H E showed that the mixing process of α-glycine in all the systems studied was exothermic.

Fermentation and complex enzyme hydrolysis enhance total phenolics and antioxidant activity of aqueous solution from rice bran pretreated by steaming with α-amylase

Lei Liu,Ruifen Zhang,Yuanyuan Deng,Yan Zhang,Juan Xiao,Fei Huang,Wei Wen,Mingwei Zhang

In this study, rice bran was successively steamed with α-amylase, fermented with lactic acid bacteria, and hydrolyzed with complex enzymes. The changes in phenolic profiles and antioxidant activities of the corresponding aqueous solutions from three stages were investigated. Compared to the first stage, fermentation and complex enzyme hydrolysis significantly increased the total phenolics, total flavonoids, total FRAP and ORAC values by 59.2%, 56.6%, 73.6% and 45.4%, respectively. Twelve individual phenolics present in free or soluble conjugate forms were also analyzed during the processing. Ferulic acid was released in the highest amount among different phenolics followed by protocatechuic acid. Moreover, a major proportion of phenolics existed as soluble conjugates. The results showed that fermentation and complex enzyme hydrolysis enhanced total phenolics and antioxidant activities of aqueous solution from rice bran pretreated by steaming with α-amylase. This research could provide basis for the processing of rice bran beverage rich in phenolics.

Carbon dots for fluorescent detection of α-glucosidase activity using enzyme activated inner filter effect and its application to anti-diabetic drug discovery

Weiheng Kong,Di Wu,Lian Xia,Xuefeng Chen,Guoliang Li,Nannan Qiu,Guang Chen,Zhiwei Sun,Jinmao You,Yongning Wu

Recently, α-glucosidase inhibitor has been widely used in clinic for diabetic therapy. In the present study, a facile and sensitive fluorescent assay based on enzyme activated inner filter effect (IFE) on nitrogen-doped carbon dots (CDs) was first developed for the detection of α-glucosidase. The N-doped CDs with green emission were prepared by a one-step hydrothermal synthesis and gave the fluorescence quantum yield of 30%, which were used as the signal output. Through α-glucosidase catalysis, 4-nitrophenol was released from 4-nitrophenyl-α- d -glucopyranoside (NGP). Interestingly, the absorption of 4-nitrophenol and the excitation of CDs were completely overlapping. Due to its great molar absorptivity , 4-nitrophenol was capable of acting as a powerful absorber to affect the fluorescent signal of CDs (i.e. IFE). By converting the absorption signals into fluorescence signals, the facile fluorescence assay strategy could be realized for α-glucosidase activity sensing, which effectively avoided the complex modification of the surface of CDs or construction of the nanoprobes. The established IFE-based sensing platform offered a low detection limit of 0.01 U/mL (S/N = 3). This proposed sensing approach has also been expanded to the inhibitor screening and showed excellent applicability. As a typical α-glucosidase inhibitor, acarbose was investigated with a low detection limit of 10 −8  M. This developed method enjoyed many merits including simplicity, lost cost, high sensitivity, good reproducibility and excellent selectivity , which also provided a new insight on the application of CDs to develop the facile and sensitive biosensor .

In vitro and in vivo evaluation of redox-responsive sorafenib carrier nanomicelles synthesized from poly (acryic acid) -cystamine hydrochloride-D-α-tocopherol succinate

Yu Liu,Jia Yang,Xin Wang,Ju Liu,Zhaobo Wang,Hongsheng Liu,Lijiang Chen