Effect of hypoxia on infiltration and migration of lung cancer cells and expression of MMP-2 and TIMP-2 / 中国肺癌杂志

<p><b>BACKGROUND</b>It has been known that different degrees of hypoxia can produce different effects on tumor. The study is to investigate the effect of hypoxia on the infiltration and migration of lung adenocarcinoma cells.</p><p><b>METHODS</b>Lung adenocarcinoma cells were exposed to normoxic (air, 5%O₂), hypoxic (1%O₂, 5%CO₂, 94%N₂) or anoxic (95%N₂, 5%CO₂) condition for 48 hours. The migration ability of the cells was assayed by wound healing methods. The infiltration ability was assayed by HABM-HEM model. The cells exposed to hypoxia were planted subcutaneously in nude mice, and the growth of cells and the rate of metastasis to lymph node or lung were observed. The levels of matrix metalloproteinase 2 (MMP-2) and tissue inhibitor of metalloproteinase II (TIMP-2) in culture media were assayed by ELISA.</p><p><b>RESULTS</b>Comparing with normoxia group, the infiltration, migration and metastasis of hypoxia group were increased significantly (P < 0.05) , as well as the level of MMP-2 (P < 0.01), and the TIMP-2 level was remarkably decreased (P < 0.05) . In anoxia group, the levels of MMP-2 and TIMP-2 were both significantly decreased (P < 0.01).</p><p><b>CONCLUSIONS</b>Moderate hypoxia can up-regulate the expression of MMP-2, down-regulate the expression of TIMP-2, and increase the infiltration and migration of lung cancer cells. But serious hypoxia can decrease the expression of MMP-2 and TIMP-2, and inhibit the proliferation, infiltration and migration of lung cancer cells.</p>

Changes in gap junctional intercellular communication in rabbits lens epithelial cells induced by low power density microwave radiation / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To demonstrate the changes in gap junctional intercellular communication (GJIC) mediated by low power density microwave radiation in rabbits lens epithelial cells (LECs) and its mechanisms.</p><p><b>METHODS</b>Rabbits' eyes were exposed to 5 mW/cm(2) and 10 mW/cm(2) power densities of microwave radiation for 3 hours. The fluorescence-recovery-after-photobleaching (FRAP) method was used to determine the GJIC. The localization and function of connexin 43 in LECs was detected by laser scanning confocal microscopy.</p><p><b>RESULTS</b>The GJIC of rabbits LECs was inhibited by microwave radiation especially in the 10 mW/cm(2) irradiated samples. A decrease in connexin 43-positive staining was seen in 5 mW/cm(2) x 3 h treated LECs. Intracellular space accumulation and cytoplasmic internalization were clearly demonstrated in 10 mW/cm(2) group.</p><p><b>CONCLUSIONS</b>Low power densities microwave radiation (5 mW/cm(2) and 10 mW/cm(2)) induces damage to connexin 43 and inhibits the GJIC of rabbits LECs. These changes result in an osmotic imbalance within the lens and induce early cataract. 5 mW/cm(2) or 10 mW/cm(2) microwave radiation is cataractogenic.</p>

Localization of the connexin 43 gap-junction protein in silica-exposed alveolar epithelial cells / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the effect of supernatants from silicon dioxide(SiO2) stimulated pulmonary alveolar macrophages(PAM) on the localization of connexin 43(Cx43) so as to explore the inhibition level of SiO2 on alveolar epithelial cellular gap-junctional communication(GJIC).</p><p><b>METHODS</b>The supermatants from the primary cultured PAM were prepared, and then added 5% (v/v) SiO2 into 2% (v/v) NBS RPMI 1640 to stimulate the normal mink lung epithelial cell line CCL-64 for 24 hours. The localizations of Cx43 in CCL-64 were analyzed by indirect immunofluorescence histochemistry and laser confocal scanning microscopy(LCSM).</p><p><b>RESULTS</b>The normal cultured CCL-64 cells displayed bright membrane-associated Cx43 plaques labeling and formed dashes at regions of intercellular junction. Being exposed to supernatants from SiO2-stimulated PAM, the CCL-64 cells retained a relative low degree of Cx43 labeling at the cell periphery, localized in cytoplasm, and the individual spot, rather than plaques, were smaller compared to normal cultured cells. Along with the increase of the concentrations of SiO2, the cells displayed a different staining pattern, with clear cluster labeling aggregating towards the nucleus.</p><p><b>CONCLUSION</b>The altered localization of the gap-junctional protein Cx43 in alveolar epithelial cells, mediated by SiO2, indicated that the internalization of Cx43 may contribute to the inhibition on GJIC in silica-induced lung epithelium injury.</p>

Downregulation of gap junctional intercellular communication induced by silicon dioxide in the pulmonary alveolar epithelial cell / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the effect of silica dioxide(SiO2) on proliferation and downregulation of gap junctional intercellular communication (GJIC) in pulmonary alveolar epithelial cells (CCL-64 cells).</p><p><b>METHODS</b>The pulmonary alveolar macrophages(PAMs) were incubated in the serum-free RPMI 1640 containing the various concentration of SiO2 for 24 hours. The supernatants were prepared and added 5% (V/V) into 2% (V/V) NBS RPMI 1640 to stimulate the proliferation of CCL-64 cells for 24 hours. A set of "blank control", run in parallel, contained RPMI 1640 + 2% (V/V) NBS alone. The proliferation of CCL-64 cells was detected using MTT assay(to show as the absorbency, A570nm). GJIC function was measured using the fluorescence redistribution after photobleaching(FRAP) assay [to express as the transfer rate of the fluorescence, K (x 10(-3)/s)], with a laser scanning confocal microscope(LSCM, Leica TCS SP).</p><p><b>RESULTS</b>The silica-exposed PAM supernatants could induce both the proliferation(F = 9.679, P < 0.01) and downregulation of GJIC(F = 20.587, P < 0.01) of CCL-64 cells. In the range of 50-500 micrograms/ml SiO2 concentrations, the proliferation (A570nm values) and GJIC(the transfer rate, K) were fitted well in a dose-dependent manner(proliferation: r = 0.891, P < 0.05; GJIC: r = -0.943, P < 0.05).</p><p><b>CONCLUSION</b>By way of stimulating the PAM, SiO2 could inhibit GJIC function in lung alveolar epithelial cells, and induce epithelial cell proliferation. In the pathogenesis of silicosis, the downregulation of GJIC of the pulmonary epithelial cells may play an important role in silica-mediated alveolar epithelial cell injury.</p>

Electromagnetic noise blocks the gap-junctional intercellular communication suppression induced by 50 Hz magnetic field / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore whether the superposition of an electromagnetic noise can block gap-junctional intercellular communication(GJIC) suppression induced by 50 Hz 0.4 mT extremely low frequency magnetic field(ELF MF).</p><p><b>METHODS</b>Fibroblast cells of mice(NIH 3T3) were exposed to 0.4 mT ELF MF or(and) electromagnetic noise with the same intensity of MF for 24 h, and the GJIC was determined by using fluorescence recovery after photobleaching(FRAP) analysis, which was performed with a laser-scanning confocal microscope(Leica, Germany).</p><p><b>RESULTS</b>ELF MF exposure significantly inhibited GJIC with fluorescence recovery rate of 27.67% +/- 5.12% as compared with the control group(45.57% +/- 9.72%) (P < 0.01), while that of ELF MF plus noise group was (52.61% +/- 8.30%), which was significantly different from ELF MF group(P < 0.01), but not from control(P > 0.05).</p><p><b>CONCLUSION</b>Electromagnetic noise could block the GJIC suppression induced by 50 Hz 0.4 mT MF.</p>

Abnormal shift of connexin 43 gap-junction protein induced by 50 Hz electromagnetic fields in Chinese hamster lung cells / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the effects of extremely low frequency magnetic fields(ELF MF) on the amount and localization of connexin 43(Cx43) gap-junction protein in the Chinese hamster lung(CHL) cells, and to explore the mechanism of ELF MF suppression on gap-junctional intercellular communication(GJIC).</p><p><b>METHODS</b>The cells were irradiated for 24 h with 50 Hz sinusoidal magnetic field at 0.8 mT without or with 12-O-tetrade-canoylphorbol-3-acetate(TPA), 5 ng/ml for 1 h. The localization of Cx43 proteins were performed by indirect immunofluorescence histochemical analysis and detected by confocal microscopy. The second experiment was conducted to examine the quantity of Cx43 proteins level in nuclei or cytoplasm and detected by Western blotting analysis.</p><p><b>RESULTS</b>The cells exposed to TPA for 1 h displayed less bright labelled spots in the regions of intercellular junction than the normal cells. Most of Cx43 labelled spots occurred in the cytoplasm and aggregated near the nuclei. At the same time, the amount of Cx43 protein in cytoplasm were increased[(2.03 +/- 0.89) in ELF group, (2.43 +/- 0.82) in TPA group] as compared to normal control(1.04 +/- 0.17) (P < 0.01).</p><p><b>CONCLUSION</b>Inhibition on GJIC function by ELF MF alone or combined with TPA may be related with the shift of Cx43 from the regions of intercellular junction to the cytoplasm.</p>

Isolation,purification and identification of polysaccharide of Cistanche deserticola / 中草药

Object The polysaccharide (CDPS) was isolated, purified and identified from Cistanche deserticola Y. C. Ma, a Chinese materia medica. Methods The polysaccharide was extracted with hot water and precipitated by alcohol. Protein in the precipitates was removed by Sevag method. The products were further purified with column chromatography on DEAE-Sephadex A-50 and Sephacryl S-200. The CDPS was idendified by IR spectrum and UV (200-400 nm) scanning spectrum. Results IR spectrum indicates that there are typical characteristic absorption peaks of polysaccharides. UV scanning spectrum shows that there are no absorption peaks of protein and nucleic acid at point 280 nm and 260 nm. Conclusion The CDPS was identified as homogeneous one.