Lipoxin A4 reduces lipopolysaccharide-induced expression of cyclooxygenase 2 and prostaglandin E2 in human bronchial epithelial cells

AIM: To explore the effects of lipoxin A₄ on the expression of cyclooxygenase 2 (COX-2) in human bronchial epithelial cells (HBECs). METHODS: HBECs were incubated with various concentrations (0.1, 1 and 10 mg/L) of lipopolysaccharide(LPS) for 9 h, or 1 mg/L LPS for different time (3 h, 6 h and 9 h). The levels of COX-2 mRNA in HBECs and prostaglandin E₂ (PGE₂) in the culture supernatant were measured. In addition, the HBECs were exposed to lipoxin A₄ at concentration of 0, 100 and 400 μmol/L after stimulated with LPS at concentration of 1 mg/L for 9 h, and the supernatant of the culture cells was collected for determining the content of PGE₂ by ELISA. The cells were also harvested, and the mRNA and protein levels of COX-2 were analyzed by RT-PCR and Western blotting, respectively. RESULTS: LPS increased the mRNA expression of COX-2 and production of PGE₂ in a dose and time dependent manners in HBECs. Induction of COX-2 mRNA and protein by LPS were inhibited by lipoxin A₄ in a dose-dependent manner. Lipoxin A₄ also significantly decreased LPS-induced production of PGE₂. CONCLUSION: Lipoxin A₄ down-regulates LPS-induced expression of COX-2 and consequently inhibits the production of PGE₂ in HBECs.     

Effects of lipoxin A4 on proliferation and IL-2/IL-2 receptor expression in Jurkat T cells

AIM: To investigate the effect of lipoxin A4 on the proliferation and IL-2 production in Jurkat T cells. METHODS: Jurkat T cells were activated in vitro with anti-CD3 (2 mg/L) and anti-CD28 (2 mg/L) antibodies in the absence or presence of lipoxin A4 (0.1 nmol/L-100 nmol/L) for 24 h, then ［3H］-TdR was added into the medium and radioactivities were measured by scintillation counting. The concentrations of IL-2 in the supernants were determined by ELISA. Cells were harvested and the expression of CD25 was assessed by FCM. For analysing the cell cycle, the cells were stained with PI and DNA contents were detected by FCM. RESULTS: Lipoxin A4 suppressed the proliferation of anti-CD3 and anti-CD28 antibodies activated Jurkat cells in a dose-dependent manner, which was associated with reduced proportion of S phase cells. Furthemore, lipoxin A4 significantly inhibited the production of IL-2 but had no obvious effect on CD25 expression. CONCLUSION: Lipoxin A4 can suppress proliferation of activate Jurkat cells and IL-2 production, through which lipoxin A4 might negatively regulate immune response.     

Prostaglandin E2 receptors,EP2 and EP4, regulate expression of surface molecules and cytokines in B-cells of collagen-induced arthritic mice

AIM: To observe the immunoregulatory effects of prostaglandin E₂ receptor (EP) subtypes EP2/EP4 on the B-cells of collagen-induced arthritic(CIA)mice. METHODS: DBA/1 mice were immunized with chicken type II collagen emulsified in Freunds complete adjuvant to induce arthritis. B-cells were isolated from the splenocyte suspension by positive selection using anti-CD19 monoclonal antibody immunomagnetic beads. The expression of MHC II, CD 80 and CD86 was examined by flow cytometry. The mRNA levels of EPs, interferon γ (IFN-γ), tumor necrosis factor α (TNF-α), IL-6, IL-4, IL-10 and transforming growth factor-β (TGF-β) were detected by real-time RT-PCR. RESULTS: The rank of the mRNA levels of EPs was EP2>EP1>EP3>EP4 in B-cells and EP2/EP4 mRNA expression was obviously increased in CIA mice. EP2 antagonists inhibited the expression of MHC II, CD80 and CD86. EP4 antagonist had little effect on CD80. EP2/EP4 antagonists inhibited the mRNA expression of IFN-γ, TNF-α, and IL-6 (P<0.05 or P<0.01) and increased the expression of IL-10 (P<0.01 or P<0.05). Furthermore, the antagonists of EP2 and EP4 also increased the mRNA expression of IL-4 and TGF-β (P<0.01), respectively. CONCLUSION: PGE₂ modulate the pathogenesis of CIA via EP2/EP4 by regulating the expression of surface molecules and cytokines in B-cells. EP2/EP4 may be a new therapeutic target for treating rheumatoid arthritis.     

Effects of ancymidol and gibberellins A3 and A4+7 on Tulipa gesneriana L. cv. Paul Richter during development in the greenhouse

The influence of soil drench applications of ancymidol (0.5 mg), GA₃ (25 mg), and Ga₄₊₇ (25 mg) was determined on the growth and development of the tulip under greenhouse conditions. Ancymidol applied on greenhouse day 1 or 6 significantly reduced the total length of the scape. Maximum reduction in growth occurred in the first internode, with a declining effect on internodes 2, 3 and 4. GA₄₊₇ applied simultaneously with ancymidol completely reversed the ancymidol effects. GA₃ was relatively ineffective. Compared to control plants, ancymidol reduced the number of cell divisions in the first internode, but not in the fourth internode. Cells of ancymidol treated plants were reduced in length and exhibited greater radial expansion. Ancymidol reduced the fresh weight of the stem and tended to conserve the fresh weight of the mother scales. The effect on the leaves and roots was variable. Ancymidol tended to increase the fresh weight of the daughter bulblets. There was no significant effect of ancymidol or the GA's on floral morphology or the number of days to flower in the greenhouse.     

Effects of schisandrin B on apoptosis of lens epithelial cells treated with H2O2

AIM: To investigate the effects of Schisandrin B (Sch B) on apoptosis of lens epithelial cells (LEC) treated with H₂O₂. METHODS: Eyes in SDrats were excised and lenses were separated under operating microscope in sterilized condition. Lenses were divided randomly into four groups with different treatment: control group, hydrogen peroxide group (H₂O₂), pirenoxine sodium group (PS) and schisandrin Bgroup (Sch B). Lenses were incubated in CO₂ incubator for 24 h with 300 μmol·L^-1 H₂O₂ and with or without 0.5 mmol·L^-1 Sch B. LECaoptosis and apoptosis rate were measured by TUNELmethod. Ultrastructure changes and apoptosis bodies of LECwere observed via transmitted electron microscope. RESULTS: (1) Apoptosis rate in H₂O₂ group (92.0±2.6) was significantly higher than that in control group (3.5±1.8). Apoptosis rate in Sch Bgroup (13.8±3.27) was remarkably lower than that in H₂O₂ group and PSgroup. (2) Ultrastructure observation indicated that apoptosis cells occurred in most LEC in H₂O₂ group and the changes were severe presenting different stages. While a few apoptosis cells were observed in Sch Bgroup, the changes were slight and most of them were in early and middle stages. CONCLUSION: These data indicated that Sch Bsignificantly inhibited apoptosis of LECduring experimental oxidative injury, the effects were stronger than PS.     

全国设施蔬菜生产可持续发展学术研讨会在沈阳召开

会议由中国园艺学会主办 ,中国农业工程学会设施园艺工程专业委员会协办 ,沈阳农业大学园艺系承办 ,于 2 0 0 0年 4月 19日至 2 2日在沈阳农业大学召开。来自我国 13个省、自治区、直辖市的与会代表共 78人 ,会议论文 4 3篇 ,由沈阳农业大学学报专刊发表。经承办单位和与会者努力 ,会议圆满成功。开幕式由中国园艺学会副理事长李树德研究员主持 ,辽宁省科技厅、农业厅、沈阳市副食品局、沈阳农业大学的领导到会祝贺并发表讲话。会议就确定的主题进行了大会发言 ,小组讨论及现场考察。代表们欣喜地看到 ,近 2 0年来我国蔬菜设施生产迅猛发展 …     

Protective effect of HSP70 on injuried myocardial cells induced by H2O2

AIM: To investigate the role of heat-shock protein 70(HSP₇₀) in the protection of myocardial cells against ischemic injury.METHODS: Myocardial cells were cultured in vitro. HSP₇₀ was induced by hyperthermia. H₂O₂-injured myocardial cells were divided into different groups. Flow cytometry, DNA Ladder and biochemistry methods were employed to observe the myocardial cells of different groups.RESULTS: Immunohistochemistry showed hyperthermia induced the up-regulation of HSP₇₀ in myocardial cells. Apoptotic rate, activity analysis of cytochrome C and succinic dehydrogenase in H₂O₂-injuried and HSP₇₀-protected groups were obviously different. Electron micrograph shomed hyperthermia alliviated myocardial cell injury induced by H₂O₂. CONCLUSION: HSP₇₀ delays apoptosis and protects against H₂O₂-induced myocardial cell injury.     

Effects of elevated CO2 on growth and morphological characteristics of ornamental bromeliads

Three ornamental bromeliads, i.e. Aechmea ‘Maya’ (CAM), Aechmea fasciata ‘Primera’ (CAM) and Guzmania ‘Hilda’ (C₃) were grown under greenhouse conditions at ambient (380 ppm) and elevated (750 ppm) CO₂. The effects of long-term exposure (34 weeks) to elevated CO₂ on growth and morphological traits constituting the ornamental value were assessed.     

Fruit set and June drop in Cox's Orange Pippin apple as affected by pollination and treatment with a mixture of gibberellins A4 and A7

Single spray applications of 100 ppm of a mixture of the gibberellins A₄ and A₇ (GA_{4 + 7}) were made on fruiting spurs of the apple cultivar Cox's Orange Pippin to investigate the effect on set, June drop and growth of fruits, as well as on shoot development and flower-bud formation on the bourses. Applications were made from 1 to 50 days after full bloom following partial hand-pollination of flowers, i.e. two stigmas per flower pollinated. In another experiment applications were made from 1 to 20 days after full bloom following complete (five stigmas per flower) or partial (two stigmas per flower) hand-pollination, after open pollination, or on emasculated flowers.GA_{4 + 7} only temporarily increased fruit set after open pollination or after effemination of flowers, and then only after application 1 day after full bloom. GA_{4 + 7} did not affect the very high fruit set after complete or partial hand-pollination. Both latter pollination treatments induced an equally high fruit set.GA_{4 + 7} reduced June drop significantly whenever fruits were left after first drop, except after early applications following open pollination. GA_{4 + 7} was effective in June-drop reduction up to 40 days after full bloom, i.e. until the onset of the June drop.Fruit size was not clearly affected by GA_{4 + 7}. The smaller fruits obtained in some cases after GA treatment could be explained by assuming that maturity was reached by fruits that would have abscised without an exogenous GA_{4 + 7} supply. GA_{4 + 7} also increased seed abortion. Fruit length was increased by GA_{4 + 7} only for applications made up to 20 days after full bloom.GA_{4 + 7} stimulated bourse-shoot development to some extent. Flower-bud formation on the bourses was not clearly affected by GA_{4 + 7}, but was markedly influenced by the presence of fruits.That GA_{4 + 7} reduced June drop so much in spite of a slight promotive effect on bourse-shoot growth and a slight abortive action on seeds suggests that these gibberellins may be specific stimuli for apple-fruit growth after actual fruit set is achieved.     

不同浓度MgSO4和KH2PO4对香菇液体培养生长量的影响

本文研究了MgSO4、KH2PO4二种元机物与香菇Cr-02液体发酵生长量的关系。结果证明：在27℃摇床转速为134r/min的培养条件下，MgSO4浓度0.05%，KH2PO4浓度为0.10%，发酵96h香菇生长量最大，发酵液透光率T在630nm波长时达135.8%，其湿菌体产量32.6g/100mL，发酵液由深褐色变成黄色、粘度大、透明，菌丝体个体较大且数目较多。     

Effects of P2X4 receptor in spinal microglia on rrTNF-induced pathological pain

AIM: To investigate the effects of P2X₄ receptor on peri-sciatic administration of recombinant rat TNF-α (rrTNF)-induced mechanical allodynia. METHODS: Male Sprague-Dawley rats (180~200 g) were used in the experiments. The levels of P2X₄ receptor on day 3, day 7 and day 14 after peri-sciatic administration of rrTNF were examined by Western blot, and the location of P2X₄ receptor in the spinal dorsal horn was observed by double immunofluorescence staining. The changes of 50% paw-withdrawal thresholds of the rat were detected by behavioral test, and the level of TNF-α in the spinal dorsal horn was also examined by Western blot when TNP-ATP was intrathecally injected before the administration of rrTNF. RESULTS: Compared with control group, the expression of P2X₄ receptor in the spinal dorsal horn on the ipsilateral side significantly increased on day 3, day 7 and day 14 (P<0.01) after rrTNF (100 ng/L) administration. P2X₄ receptor was co-localized only with microglia, but not with neurons or astrocytes. Intrathecal injection of TNP-ATP before rrTNF administration prevented mechanical allodynia induced by rrTNF and inhibited the upregulation of TNF-α in the spinal dorsal horn. CONCLUSION: P2X₄ receptors in microglia may be involved in rrTNF-induced mechanical allodynia by the upregulation of TNF-α in the spinal dorsal horn.     

Effects of A2a adenosine receptor on hypoxic pulmonary hypertension in rats treated with salidroside

AIM: To study the protective effect of A_2a adenosine receptor (A_2aAR) on hypoxic pulmonary hypertension in the rats treated with salidroside. METHODS: Sprague-Dawley rats were randomly divided into 6 groups: normal control group, hypoxia group, hypoxia+salidroside (low dose) group, hypoxia+salidroside (median dose) group, hypoxia+salidroside (high dose) group, and hypoxia+CGS-21680 (a selective agonist of A_2aAR) group. Pulmonary hypertension in the rats was produced for 4 weeks. Mean pulmonary artery pressure (mPAP), mean carotid arterial pressure (mCAP) and the weight ratio of right ventricle/(left ventricle+septum)［RV/(LV+S)］ were measured. The expression of A_2aAR in the pulmonary arterioles was determined by immunohistochemistry and in situ hybridization. The mRNA expression of A2aAR in the lung tissues was detected by real-time RT-PCR. The protein level of A_2aAR in the lung tissues was analyzed by Western blotting. RESULTS: The mPAP in hypoxia group was significantly higher than that in normal control group. The mPAP in hypoxia+salidroside (high dose) group and CGS-21680 group was significantly lower than that in hypoxia group. RV/(LV+S) in hypoxia group were significantly higher than that in normal control group. RV/(LV+S) in hypoxia+salidroside (median dose) group, hypoxia+salidroside (high dose) group and CGS-21680 group were lower than that in hypoxia group. The ratio of vessel wall area/vessel total area (WA/TA) in hypoxia group was significantly higher than that in normal control group. WA/TA in hypoxia+salidroside (low dose) group, hypoxia+salidroside (median dose) group, hypoxia+salidroside (high dose) group and CGS21680 group were obviously lower than that in hypoxia group. The expression of A_2aAR was significantly higher in hypoxia group than that in normal control group. The expression of A_2aAR in hypoxia+salidroside (high dose) group and CGS-21680 group was obviously higher than that in hypoxia group. CONCLUSION: The A_2aAR attenuates pulmonary vessel remodeling and pulmonary hypertension induced by hypoxia. Salidroside protects the pulmonary vessel from remodeling and inhibits the development of hypoxia-induced pulmonary hypertension by up-regulation of A_2aAR expression.     

Effects of iPSC-MSCs on mitochondria of PC12 cells injured by CoCl2

AIM: To investigate the effects of induced pluripotent stem cells-derived mesenchymal stem cells (iPSC-MSCs) on cobalt chloride (CoCl₂)-induced injuries of PC12 cells and its possible mechanism. METHODS: PC12 cells were exposed to CoCl₂ to set up a chemical-induced cellular injury model and were cocultured with iPSC-MSCs. The cell viability was tested by CCK-8 assay. The apoptosis was measured by flow cytometry using Annexin V/PI staining. The mitochondrial membrane potential (MMP) was analyzed by flow cytometry using JC-1 staining. Immunofluorescence was employed to observe mitochondrial transfer from iPSC-MSCs to PC12 cells. RESULTS: Apoptosis of PC12 cells was increased and MMP of PC12 cells was decreased after exposed to CoCl₂ at concentration of 400 μmol/L for 24 h. Coculture of PC12 cells with iPSC-MSCs reduced the apoptosis and recovered the MMP of the PC12 cells. Tunneling nanotubes were formed between iPSC-MSCs and PC12 cells, through which the iPSC-MSCs transferred the mitochondria to the PC12 cells. CONCLUSION: iPSC-MSCs protect PC12 cells from CoCl₂-induced injuries, which may be associated with the mitochondrial transfer from iPSC-MSCs to PC12 cells.     

Effects of endothelial nitric oxide synthase gene transfection on cytokines and cAMP production in human phagocytic cells

AIM and METHOD: Human endothelial nitric oxide synthase (eNOS) gene was transfected into human phagocytic cell U937 and the effects of gene transfer on cytokines and cAMP production were observed. RESULTS: A functional eNOS was stably expressed in transfected U937 cells, but NO release was undetectable in intact transfectants. However, eNOS gene expression upregulated tumor necrosis factor-α release and downregulated interleukin-10 and cAMP production in either presence or absence of NOS inhibitor N^ω-monomethyl-L-arginine. CONCLUSION: The function of tranfected eNOS gene product showed cellular speciality. The effector molecule that changed the produced pattern of cytokines and cAMP in phagocytic cells seems not likely the nitric oxide.     

The relationship between the activity of phospholipase A2 and chronic hypoxic pulmonary hypertension

AIM:To study the relationship between the activity of phospholipase A₂ (PLA₂) and chronic hypoxic pulmonary hypertension. METHODS:29 healthy SD rats were randomly divided into normal control group, chronic hypoxic group and hypoxia plus Polidatin (PD) group. The model of rat chronic hypoxic pulmonary hypertension was made by method of intermittent isobaric hypoxia for 21 days. The mean pulmonary arterial pressure (mPAP) was measured by inserting a microcatheter into the pulmonary artery. RESULTS:After exposing hypoxia for 21 days, the mPAP, R/L+S, the PLA₂ activity, TXB₂, MDA in plasma and lung homogenate increased significantly, while 6-k-PGF_1α, SOD decreased significantly. Pretreatment with PD could relieve the changes mentioned above.CONCLUSION:PLA₂ plays an important inducing role through its metabolic products and the interactional radicals in the formation of chronic hypoxic pulmonary hypertension.     

Effects of lovastatin on differentially expressed genes in HepG2 cells

AIM: To analyze the lovastatin-induced differential gene expression in HepG2 cells using a cDNA microarray assay. METHODS: Total RNA was extracted from the lovastatin-treated HepG2 cells and control group. cDNA was synthesized from RNA with Cy3/Cy5-labelled dCTP. Then the hybridization was conducted. The result was analyzed using Imagene and Genespring software. RT-PCR was carried to confirm the hybridization results. RESULTS: 30 genes were up-regulated while 11 genes were down-regulated in lovastatin-treated HepG2 cells, involved in some major functional areas including signal transduction, cell cycle regulation, tumor immunity, and so on. CONCLUSION: The analysis of differentially expressed genes in lovastatin-treated HepG2 cells is helpful to explore the mechanism of the anti-tumor activity of statins.     

Changes of PGE2, PGI2 and TXA2 concentration in rat traumatic pulpitis

AIM: To study the relationship between prostaglandins and acute pulpitis. METHODS: Rat traumatic pulpitis model was established by pulp exposure. The kinetic pathological changes in dental pulpal tissues and changes of PGE₂,6-Keto-PGF_1α and TXB₂ concentration in dental pulp were observed. RESULTS: After pulpal trauma, the dental pulp showed inflammatory changes and the concentrations of PGE₂,6-Keto-PGF_1α and TXB₂ were increased, which peaked at 6 hour post-trauma. CONCLUSION: Prostaglandins play a significant role in the pathogenesis of pulpitis.     

Effects of TKTL1 silencing by siRNA on growth microenvironment of human hepatocellular carcinoma HepG2 cells

AIM:To explore the relationship between the expression of transketolase-like 1 protein(TKTL1) and the metastasis of hepatocellular carcinoma by investigating the change of some indicators in growth microenvironment including lactate production, reduced glutathione(GSH) level and ratio of NADPH/NADP⁺ in hepatocellular carcinoma cell line HepG2 after silencing of TKTL1 expression by siRNA. METHODS:Specific siRNA expression vector targeting TKTL1 gene was constructed and transfected into HepG2 cell line. The effect of TKTL1 silencing was evaluated by detecting the mRNA level and the activity of transketolase(TKTL1). The changes of lactate production, GSH level, the ratio of NADPH/NADP⁺ and glucose-6-phosphate dehydrogenase(G-6-PD) activity were observed in transfected HepG2 cells compared with the untransfected control cells. RESULTS:Compared with the untransfected control cells, the mRNA expression of TKTL1 and the TKT activity decreased significantly(P<0.01). Meanwhile, the lactate production, GSH level and ratio of NADPH/NADP⁺ also decreased significantly(P<0.01). However, no change of the G-6-PD activity was observed. CONCLUSION:Carcinoma cells switch the glucose metabolism by overexpression of TKTL1 to modify the lactate production and the levels of reactive oxygen species, thus changing the growth microenvironment in favor of tumor metastasis.     

β-elemene reverses hepatocyte growth factor-induced resistance to gefitinib in PC-9 lung cancer cells via c-Met pathway

AIM: To investigate the effect of β-elemene on reversing hepatocyte growth factor (HGF)-induced resistance to gefitinib in PC-9 cells, and to explore its possible mechanisms. METHODS: The gefitinib-resistant PC-9 cells induced by HGF were treated with β-elemene or/and gefitinib. The cell activity was measured by MTT assay. The effect of β-elemene on the invasion ability in HGF-induced resistance to gefitinib in PC-9 cells was detected by Transwell migration assay. The protein levels of p-Met, c-Met, p-AKT and AKT in PC-9 cells of each group were determined by Western blot. RESULTS: The results of MTT assay showed that the cell activity of PC-9 cells was significantly inhibited by β-elemene (P<0.05). IC₅₀ of β-elemene for PC-9 cells was 169.31 mg/L. IC₅₀ of gefitinib for PC-9 cells was 0.30 μmol/L. Exogenously adding recombinant HGF induced significantly resistance to gefitinib in PC-9 cells. Moreover, SU11274 (an inhibitor of c-Met) significantly decreased the viability of the cells exposed to HGF and gefitinib (P<0.05). Combined treatment with β-elemene and gefitinib in the presence of HGF (50 μg/L) significantly decreased the viability of PC-9 cells as compared with the PC-9 cells treated with gefitinib alone in the presence of HGF (P<0.05), so did the result of the cell migration. The protein levels of p-Met and p-AKT were significantly up-regulated by HGF, while the protein levels of p-Met and p-AKT were markedly down-regulated in the cells treated with β-elemene and gefitinib compared with gefitinib alone in the presence of HGF. CONCLUSION: β-elemene reverses HGF-induced resistance to gefitinib in lung cancer PC-9 cells, likely due to the inhibition of HGF-induced activation of c-Met and its down streams signaling pathways (P<0.01).