胃饥饿素对小鼠急性肺损伤的保护作用及其机制研究

目的 探讨胃饥饿素对小鼠急性肺损伤的保护作用和机制.方法 将60只小鼠采用随机数字表法分为6组:对照组、模型组、胃饥饿素低、中、高剂量组和地塞米松组.对照组和模型组腹腔注射0.2 mL生理盐水,胃饥饿素各组分别注射400、200、100 μg/kg溶液,地塞米松组注射2 mg/kg.给药后1h,对照组滴注等体积生理盐水...     

牛磺酸对大鼠肢体缺血/再灌注后肺组织损伤的保护作用

目的:观察大鼠肢体缺血再灌注(LIR)后肺组织形态学的变化及牛磺酸对其影响.方法:Wistar大鼠随机分为3组,对照组(control)、缺血/再灌注组(LIR)、牛磺酸 缺血/再灌注组(Tau LIR),各组动物通过大体、光镜和透射电镜观察肺组织形态学变化,并测定肺系数和肺通透指数及肺组织活性氧和MDA含量.结果:大鼠LIR后肺组织出现以肺泡毛细血管膜通透性增加为特征的组织细胞损伤,光镜下显示毛细血管扩张充血、血管周围间隙增大、肺泡腔中有大量蛋白渗出物,电镜下可见肺泡上皮细胞之间、毛细血管内皮之间的紧密连接松解;肺系数和肺通透指数升高;肺组织活性氧及MDA含量增加.提前给予外源性牛磺酸可使肺组织损伤变化减轻.结论:牛磺酸对大鼠LIR后肺损伤有保护作用,其保护机理之一与其抗氧化,保护细胞之间的紧密连接有关.     

Endogenous Expression of Adenosine A<Subscript>1</Subscript>, A<Subscript>2 </Subscript>and A<Subscript>3</Subscript> Receptors in Rat C6 Glioma Cells

Inhibitory and stimulatory adenosine receptors have been identified and characterized in both membranes and intact rat C6 glioma cells. In membranes, saturation experiment performed with [³H]DPCPX, selective A₁R antagonist, revealed a single binding site with a K _D = 9.4 ± 1.4 nM and B _max = 62.7 ± 8.6 fmol/mg protein. Binding of [³H]DPCPX in intact cell revealed a K _D = 17.7 ± 1.3 nM and B _max = 567.1 ± 26.5 fmol/mg protein. On the other hand, [³H]ZM241385 binding experiments revealed a single binding site population of receptors with K _D = 16.5 ± 1.3 nM and B _max = 358.9 ± 52.4 fmol/mg protein in intact cells, and K _D = 4.7 ± 0.6 nM and B _max = 74.3 ± 7.9 fmol/mg protein in plasma membranes, suggesting the presence of A_2A receptor in C6 cells. A₁, A_2A, A_2B and A₃ adenosine receptors were detected by Western-blotting and immunocytochemistry, and their mRNAs quantified by real time PCR assays. Giα and Gsα proteins were also detected by Western-blotting and RT-PCR assays. Furthermore, selective A₁R agonists inhibited forskolin- and GTP-stimulated adenylyl cyclase activity and CGS 21680 and NECA stimulated this enzymatic activity in C6 cells. These results suggest that C6 glioma cells endogenously express A₁ and A₂ receptors functionally coupled to adenylyl cyclase inhibition and stimulation, respectively, and suggest these cells as a model to study the role of adenosine receptors in tumoral cells.     

Rad9 is upregulated and plays protective roles in an acute lung injury model

The Rad9-Hus1-Rad1 protein complex is believed to respond to DNA damage and play important roles in the cell cycle. We studied the role of Rad9 protein in alveolar epithelial cells in the pathogenesis of acute lung injury. In a mouse model of lung injury induced by bleomycin or lipopolysaccharide, Rad9 expression is increased in type II alveolar epithelial cells from the early stage of lung injury. A549 cells and mouse primary alveolar epithelial cells also upregulated Rad9 expression after exposure to bleomycin. Gene silencing of Rad9 using siRNA decreased the G2/M arrest in A549 cells induced by bleomycin and also decreased the survival of A549 cells following exposure to bleomycin and hydrogen peroxide. In conclusion, Rad9 is a signal in the earlier stage of epithelial cell cycle regulation and plays protective roles in alveolar epithelial cells in the pathogenesis of acute lung injury.     

Sublethal concentration of H<Subscript>2</Subscript>O<Subscript>2</Subscript> enhances the protective effect of mesenchymal stem cells in rat model of spinal cord injury

Objective

To investigate the effect of H₂O₂ on the migration and antioxidant defense of mesenchymal stem cells (MSCs) and the neurotrophic effects of H₂O₂-treated MSCs on spinal cord injury (SCI).

Results

Sublethal concentrations of H₂O₂ decreased cell migration and expression of CXCR4 and CCR2 as well as Nrf2 expression in MSCs. In the second phase, transplantation of treated and untreated MSCs to SCI caused minor changes in locomotor dysfunction. There was a significantly difference between cell-treated and spinal cord injury groups in expression of BDNF (brain-derived neurotrophic factor). Transplantation of H₂O₂-treated cells caused an increase in BDNF expression compared to non-treated cells.

Conclusion

Transplantation of H₂O₂-treated stem cells may have protective effects against SCI through by increasing neurotrophic factors.

     

LncRNA NONRATT021972 involved the pathophysiologic processes mediated by P2X<Subscript>7</Subscript> receptors in stellate ganglia after myocardial ischemic injury

Adenosine triphosphate (ATP) acts on P2X receptors to initiate signal transmission. P2X₇ receptors play a role in the pathophysiological process of myocardial ischemic injury. Long noncoding RNAs (lncRNAs) participate in numerous biological functions independent of protein translation. LncRNAs are implicated in nervous system diseases. This study investigated the effects of NONRATT021972 small interference RNA (siRNA) on the pathophysiologic processes mediated by P2X₇ receptors in stellate ganglia (SG) after myocardial ischemic injury. Our results demonstrated that the expression of NONRATT021972 in SG was significantly higher in the myocardial ischemic (MI) group than in the control group. Treatment of MI rats with NONRATT021972 siRNA, the P2X₇ antagonist brilliant blue G (BBG), or P2X₇ siRNA improved the histology of injured ischemic cardiac tissues and decreased the elevated concentrations of serum myocardial enzymes, creatine kinase (CK), CK isoform MB (CK-MB), lactate dehydrogenase (LDH) and aspartate aminotransferase (AST) compared to the MI rats. NONRATT021972 siRNA, BBG, or P2X₇ siRNA treatment in MI rats decreased the expression levels of P2X₇ immunoreactivity, P2X₇ messenger RNA (mRNA), and P2X₇ protein, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and phosphorylated p38 mitogen-activated protein kinase (p38 MAPK) in the SG compared to MI rats. NONRATT021972 siRNA treatment prevented the pathophysiologic processes mediated by P2X₇ receptors in the SG after myocardial ischemic injury.     

The encapsulated lithium effect on the first hyperpolarizability of C<Subscript>60</Subscript>Cl<Subscript>2</Subscript> and C<Subscript>60</Subscript>F<Subscript>2</Subscript>

In this paper, we report a study on the structure and first hyperpolarizability of C₆₀Cl₂ and C₆₀F₂. The calculation results show that the first hyperpolarizabilities of C₆₀Cl₂ and C₆₀F₂ were 172 au and 249 au, respectively. Compared with the fullerenes, the first hyperpolarizability of C₆₀Cl₂ increased from 0 au to 172 au, while the first hyperpolarizability of C₆₀F₂ increased from 0 au to 249 au. In order to further increase the first hyperpolarizability of C₆₀Cl₂ and C₆₀F₂, Li@C₆₀Cl₂ and Li@C₆₀F₂ were obtained by introducing a lithium atom to C₆₀Cl₂ and C₆₀F₂. The first hyperpolarizabilities of Li@C₆₀Cl₂ and Li@C₆₀F₂ were 2589 au and 985 au, representing a 15-fold and 3.9-fold increase, respectively, over those of C₆₀Cl₂ and C₆₀F₂. The transition energies of four molecules (C₆₀Cl₂, Li@C₆₀Cl₂, C₆₀F₂, Li@C₆₀F₂) were calculated, and were found to be 0.17866 au, 0.05229 au, 0.18385 au, and 0.05212 au, respectively. A two-level model explains why the first hyperpolarizability increases for Li@C₆₀Cl₂ and Li@C₆₀F₂.     

The P2Y<Subscript>1</Subscript> receptor-mediated leukocyte adhesion to endothelial cells is inhibited by melatonin

Extracellular ATP (released by endothelial and immune cells) and its metabolite ADP are important pro-inflammatory mediators via the activation of purinergic P2 receptors (P2Y and P2X), which represent potential new targets for anti-inflammatory therapy. Endothelial P2Y₁ receptor (P2Y₁R) induces endothelial cell activation triggering leukocyte adhesion. A number of data have implicated melatonin as a modulator of immunity, inflammation, and endothelial cell function, but to date no studies have investigated whether melatonin modulates endothelial P2YR signaling. Here, we evaluated the putative effect of melatonin on P2Y₁R-mediated leukocyte adhesion to endothelial cells and TNF-α production, using mesenteric endothelial cells and fresh peripheral blood mononuclear cells isolated from rats. Endothelial cells were treated with the P2Y₁R agonist 2MeSATP, alone or in combination with melatonin, and then exposed to mononuclear cells. 2MeSATP increased leukocyte adhesion to endothelial cells and TNF-α production in vitro, and melatonin inhibited both effects without altering P2Y₁R protein expression. In addition, assays with the Ca²⁺ chelator BAPTA-AM indicate that the effect of melatonin on 2MeSATP-stimulated leukocyte adhesion depends on intracellular Ca²⁺ modulation. P2Y₁R is considered a potential target to control chronic inflammation. Therefore, our data unveiled a new endothelial cell modulator of purinergic P2Y₁ receptor signaling.     

The protective effect of ApolipoproteinA-I on myocardial ischemia-reperfusion injury in rats

It is well established that reperfusion of heart is the optimal method for salvaging ischemic myocardium, however, the success of this therapy could be limited by reperfusion injury, which is involved in inflammatory responses. High density lipoprotein (HDL) has an anti-inflammatory function and can protect the heart from ischemia-reperfusion (I/R) injury. In this study, we investigated the cardioprotective role of apolipoprotein A-I (ApoA-I), the major apolipoprotein of HDL, in I/R injury. Using rats subjected to myocardial I/R by ligation of left anterior descending coronary artery (LAD), we found that administration of ApoA-I (20 mg/kg, iv) before the onset of reperfusion of myocardial infarction can significantly reduce serum creatine kinase (CK) levels (62.1+/-13.8%, p<0.01) and heart TNF-alpha as well as IL-6 levels, compared with saline controls (40.4+/-14.7%, 44+/-9.8%, p<0.01 respectively). Moreover, ApoA-I treatment suppresses the expression of ICAM-1 on endothelium, thus diminishing neutrophil adherence, transendothelial migration, and the subsequent myocyte injury. We concluded that ApoA-I could effectively protect rat heart from I/R injury.     

Vanadate-induced cell death is dissociated from H<Subscript>2</Subscript>O<Subscript>2</Subscript> generation

Vanadium is an environmentally toxic metal with peculiar and sometimes contradictory cellular effects. It is insulin-mimetic, it can either stimulate cell growth or induce cell death, and it has both mutagenic and antineoplastic properties. However, the mechanisms involved in those effects are poorly understood. Several studies suggest that H₂O₂ is involved in vanadate-induced cell death, but it is not known whether cellular sensitivity to vanadate is indeed related to H₂O₂ generation. In the present study, the sensitivity of four cell lines from different origins (K562, K562-Lucena 1, MDCK, and Ma104) to vanadate and H₂O₂ was evaluated and the production of H₂O₂ by vanadate was analyzed by flow cytometry. We show that cell lines very resistant to H₂O₂ (K562, K562-Lucena 1, and Ma104 cells) are much more sensitive to vanadate than MDCK, a cell line relatively susceptible to H₂O₂, suggesting that vanadate-induced cytotoxicity is not directly related to H₂O₂ responsiveness. In accordance, vanadate concentrations that reduced cellular viability to approximately 60–70% of the control (10 μmol/L) did not induce H₂O₂ formation. A second hypothesis, that peroxovanadium (PV) compounds, produced once vanadate enters into the cells, are responsible for the cytotoxicity, was only partially confirmed because MDCK cells were resistant to both vanadate and PV compounds (10 μmol/L each). Therefore, our results suggest that vanadate toxicity occurs by two distinct pathways, one dependent on and one independent of H₂O₂ production.     

Differential Effects of Methionine and Cysteine Oxidation on [Ca<Superscript>2+</Superscript>]<Subscript>i</Subscript> in Cultured Hippocampal Neurons

Methionine and cysteine residues in proteins are the major targets of reactive oxygen species (ROS). The present work was designed to characterize the impact of methionine and cysteine oxidation upon [Ca²⁺]_i in hippocampal neurons. We investigated the effects of H₂O₂ and chloramine T(Ch-T) agents known to oxidize both cysteine and methionine residues, and 5, 5′-dithio-bis (2-nitrobenzoic acid) (DTNB)—a cysteine-specific oxidant, on the intracellular calcium in hippocampal neurons. The results showed that these three oxidants, 1 mM H₂O₂, 1 mM Ch-T, and 500 μM DTNB, induced an sustained elevation of [Ca²⁺]_i by 76.1 ± 3.9%, 86.5 ± 5.0%, and 24.4 ± 3.2% over the basal level, respectively. The elevation induced by H₂O₂ and Ch-T was significantly higher than DTNB. Pretreatment with reductant DTT at 1 mM for 10 min completely prevented the action of DTNB on [Ca²⁺]_i, but only partially reduced the effects of H₂O₂ and Ch-T on [Ca²⁺]_i, the reductions were 44.6 ± 4.2% and 29.6 ± 6.1% over baseline, respectively. The elevation of [Ca²⁺]_i induced by H₂O₂ and Ch-T after pretreatment with DTT were statistically higher than that induced by single administration of DTNB. Further investigation showed that the elevation of [Ca²⁺]_i mainly resulted from internal calcium stores. From our data, we propose that methionine oxidation plays an important role in the regulation of intracellular calcium and this regulation may mainly be due to internal calcium stores.     

The control of mitochondrial succinate-dependent H<Subscript>2</Subscript>O<Subscript>2</Subscript> production

In brain mitochondria succinate activates H₂O₂ release, concentration dependently (starting at 15 μM), and in the presence of NAD dependent substrates (glutamate, pyruvate, β-hydroxybutyrate). We report that TCA cycle metabolites (citrate, isocitrate, α-ketoglutarate, fumarate, malate) individually and quickly inhibit H₂O₂ release. When they are present together at physiological concentration (0.2, 0.01, 0.15, 0.12, 0.2 mM respectively) they decrease H₂O₂ production by over 60% at 0.1–0.2 mM succinate. The degree of inhibition depends on the concentration of each metabolite. Acetoacetate is a strong inhibitor of H₂O₂ release, starting at 10 μM and acting quickly. It potentiates the inhibition induced by TCA cycle metabolites. The action of acetoacetate is partially removed by β-hydroxybutyrate. Removal is minimal at 0.1 mM acetoacetate, and is higher at 0.5 mM acetoacetate. We conclude that several inhibitors of H₂O₂ release act jointly and concentration dependently to rapidly set the required level of H₂O₂ generation at each succinate concentration.     

Influence of cis-[PtCl<Subscript>2</Subscript>(Me<Subscript>2</Subscript>SO)<Subscript>2</Subscript>] on thermal denaturation of albumin

The interaction of cis-[PtCl₂(Me₂SO)₂] with human serum albumin (HSA) and the sensitivity of the complex to heat denaturation as dependent on the duration of incubation have been studied by UV absorption and fluorescence spectroscopy. Optimal conditions for cis-[PtCl₂(Me₂SO)₂] binding to HSA have been determined. The results are compared with the data for the HSA-cisplatin complex. It has been found that binding of HSA with cis-[PtCl₂(Me₂SO)₂] does not result in significant structural changes of the protein.     

Lung-protective effect of Punicalagin on LPS-induced acute lung injury in mice

Background: Punicalagin (Pun) is one of the main bioactive compounds in pomegranate peel, it possesses many properties, including antioxidant, anti-inflammation and immunosuppressive activities. The study was aimed to investigate the protective effect and mechanisms of Pun on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice.Methods and Results: Forty-eight BALB/c male mice were used to establish ALI by intratracheal-instilled 2.4 mg/kg LPS, the mice were randomly divided into model and Pun (10, 20, 40 mg/kg) groups. The other 12 mice were intratracheal-instilled same volume of water as control. After 2 h of receiving LPS, mice were administered drug through intraperitoneal injection. Lung index, histopathological changes, white blood cells and biomarkers in bronchoalveolar lavage fluid (BALF) were analyzed. The protein expression of total and phosphor p65, IκBα, ERK1/2, JNK and p38 in lung tissue was detected. The result showed that Pun could reduce the lung index and wet/dry weight (W/D) ratio, improve lung histopathological injury. In addition, Pun decreased the inflammation cells and regulated the biomarkers in BALF. Furthermore, Pun dose-dependently reduced the phosphor protein levels of p65, IκBα, ERK1/2, JNK and p38 in lung tissue, which exhibited that the effect of Pun related to mitogen-activated protein kinases (MAPKs) pathway. More importantly, there was no toxicity was observed in the acute toxicity study of Pun.Conclusion: Pun improves LPS-induced ALI mainly through its anti-inflammatory properties, which is associated with nuclear factor-κB (NF-κB) and MAPKs signaling pathways. The study implied that Pun maybe a potent agent against ALI in future clinic.     

Selective effects of H<Subscript>2</Subscript>O<Subscript>2</Subscript> on cyanobacterial photosynthesis

The sensitivity of phytoplankton species for hydrogen peroxide (H₂O₂) was analyzed by pulse amplitude modulated (PAM) fluorometry. The inhibition of photosynthesis was more severe in five tested cyanobacterial species than in three green algal species and one diatom species. Hence the inhibitory effect of H₂O₂ is especially pronounced for cyanobacteria. A specific damage of the photosynthetic apparatus was demonstrated by changes in 77 K fluorescence emission spectra. Different handling of oxidative stress and different cell structure are responsible for the different susceptibility to H₂O₂ between cyanobacteria and other phytoplankton species. This principle may be potentially employed in the development of new agents to combat cyanobacterial bloom formation in water reservoirs.     

Immobilization of glucose oxidase on Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/SiO<Subscript>2</Subscript> magnetic nanoparticles

Glucose oxidase (GOD) was covalently immobilized onto Fe₃O₄/SiO₂ magnetic nanoparticles (FSMNs) using glutaraldehyde (GA). Optimal immobilization was at pH 6 with 3-aminopropyltriethoxysilane at 2% (v/v), GA at 3% (v/v) and 0.143 g GOD per g carrier. The activity of immobilized GOD was 4,570 U/g at pH 7 and 50°C. The immobilized GOD retained 80% of its initial activity after 6 h at 45°C while free enzyme retained only 20% activity. The immobilized GOD maintained 60% of its initial activity after 6 cycles of repeated use and retained 75% of its initial activity after 1 month at 4°C whereas free enzymes retained 62% of its activity.     

The subcommissural organ expresses D<Subscript>2</Subscript>, D<Subscript>3</Subscript>, D<Subscript>4</Subscript>, and D<Subscript>5</Subscript> dopamine receptors

Dopamine receptors have been found in certain populations of non-neuronal cells in the brain, viz., discrete areas of ciliated ependyma and the ependymal cells of the choroid plexus. We have studied the presence of both tyrosine-hydroxylase-immunoreactive nerve fibers and dopamine receptors in the subcommissural organ (SCO), an ependymal brain gland that is located in the roof of the third ventricle and that secretes, into the cerebrospinal fluid, glycoproteins that aggregate to form Reissners fiber (RF). Antibodies against D₂, D₃, D₄, and D₅ dopamine receptors were used in immunoblots of bovine striatum, fresh SCO, and organ-cultured SCO, and in immunocytochemistry of the bovine, rat, and mouse SCO. Only a few tyrosine-hydroxylase fibers appeared to reach the SCO. However, virtually all the secretory ependymal and hypendymal cells of the SCO immunoreacted with antibodies against D₂, D₄, and D₅ receptors, with the last-mentioned rendering the strongest reaction, especially at the ventricular cell pole of the secretory ependymocytes, suggesting that dopamine might reach the SCO via the cerebrospinal fluid. The antibodies against the four subtypes of receptors revealed corresponding bands in immunoblots of striatum and fresh SCO. Although the cultured SCO displayed dopamine receptors, dopamine had no apparent effect on the expression of the SCO-spondin gene/protein or on the release of RF-glycoproteins (SCO-spondin included) by SCO explants, suggesting that dopamine affects the function(s) of the SCO differently from the secretion of RF-glycoproteins.Financial support was provided by grants PI 030756 and Red CIEN, Instituto de Salud Carlos III, Spain (to J.M.P.F.), and 1030265 from Fondecyt, Chile (to E.M.R.)     

Effect of H<Subscript>2</Subscript>O<Subscript>2</Subscript> on tyrosine phosphorylation of pea proteins

Changes in tyrosine phosphorylation of soluble polypeptides of pea (Pisum sativum L.) roots were revealed under the action of exogenous hydrogen peroxide in situ and in vitro. The polypeptides whose tyrosine phosphorylation in situ was vanadate-sensitive were identified. A thiol agent dithiothreitol and the antioxidant ascorbic acid reversed the effect of hydrogen peroxide in vitro. The results indicate that tyrosine phosphorylation of pea proteins is a subject to redox regulation.     

Theoretical study of the novel sandwich compound [Au<Subscript>3</Subscript>Cl<Subscript>3</Subscript>Tr<Subscript>2</Subscript>]<Superscript>2+</Superscript>

A theoretical study of a sandwich compound with a metal monolayer sheet between two aromatic ligands is presented. A full geometry optimization of the [Au₃Cl₃Tr₂]²⁺ (1) compound, which is a triangular gold(I) monolayer sheet capped by chlorines and bounded to two cycloheptatrienyl (Tr) ligands was carried out using perturbation theory at the MP2 computational level and DFT. Compound (1) is in agreement with the 18–electron rule, the bonding nature in the complex may be interpreted from the donation interaction coming from the Tr rings to the Au array, and from the back-donation from the latter to the former. NICS calculations show a strong aromatic character in the gold monolayer sheet and Tr ligands; calculations done with HOMA, also report the same aromatic behavior on the cycloheptatrienyl fragments giving us an insight on the stability of (1). The Au –Au bond lengths indicate that an intramolecular aurophilic interaction among the Au(I) cations plays an important role in the bonding of the central metal sheet. Figure (a) Ground state geometry of complex 1; (b) Top view of compound 1 and Wiberg bond orders computed with the MP2/B1 computational method; (c) Lateral view of compound 1 and NICS values calculated with the MP2/B1 method; the values in parenthesis were obtained at the VWN/TZP level