Borosilicate effect onin vitro biological activity of osteoblasts / 中国组织工程研究

BACKGROUND:Borosilicate cannot only be mineralized to form hydroxy carbonate apatite layer, but also have strong chemical reactivity to promote bone cel regeneration. OBJECTIVE:To investigate the effect of the borosilicate bioglass on the growth behavior of rabbit osteoblasts through in vitro culture experiment. METHODS:The initial and secondary extracts of borosilicate bioglass were prepared according to the requirement of ISO10993-12: 2007. The bone marrow mesenchymal stem cels of rabbits were isolated and cultured. The second generation bone marrow mesenchymal stem cels were induced to differentiate into osteoblasts. The osteoblasts of the 5th-15th RESULTS AND CONCLUSION:The osteoblasts proliferation in the initial extract and secondary extract groups was better than that in the α-MEM medium group (P < 0.05). The osteoblasts proliferation in the initial extract group was better than that in the secondary extract group (P < 0.05). The total protein content of osteoblasts in the initial extract group was higher than that in the secondary extract and α-MEM medium group (P < 0.05). There were no significant differences in the alkaline phosphatase activity, apoptosis rate, horizontal migration distance of osteoblast and transmembrane cel number in Transwel between these three groups. These results demonstrate that borosilicate bioglass has good biocompatibility and has a certain benign regulatory role in generations were obtained and cultured with the initial and secondary extracts of borosilicate bioglass and α-MEM medium, respectively. The effects of borosilicate bioglass on the osteoblasts proliferation, protein synthesis, alkaline phosphatase activity, cel apoptosis, and cel migration in horizontal and vertical direction were observed.RESULTS AND CONCLUSION: The osteoblasts proliferation in the initial extract and secondary extract groups was better than that in the α-MEM medium group (P < 0.05). The osteoblasts proliferation in the initial extract group was better than that in the secondary extract group (P < 0.05). The total protein content of osteoblasts in the initial extract group was higher than that in the secondary extract and α-MEM medium group (P < 0.05). There were no significant differences in the alkaline phosphatase activity, apoptosis rate, horizontal migration distance of osteoblast and transmembrane cell number in Transwell between these three groups. These results demonstrate that borosilicate bioglass has good biocompatibility and has a certain benign regulatory role in osteoblast proliferation.

Phosphorylation of NF-κB P65 subunit mediates chemical hypoxia-induced inflammatory injury in HaCaT cells / 中华皮肤科杂志

Objective To explore whether the phosphorylation of NF-κB P65 subunit is involved in the cytotoxicity to and inflammation in an immortal human keratinocyte cell line HaCaT during cobalt chloride (CoCl2-induced chemical hypoxia. Methods HaCaT cells were treated with CoCl2 of 2 mmol/L to set up a chemical hypoxia-induced cell model of injury. Then, RNA interference was used to down-regulate the expression of P65 in CoCl2-induced HaCaT cells. After additional culture, cell viability was tested by cell counting kit8 (CCK-8), the levels of interleukin 6 (IL-6) and interleukin 8 (IL-8) were detected by ELISA kits, phosphorylated and total P65 protein was measured by Western blot. Results The exposure of HaCaT cells to 2 mmol/L CoCl2 for 0 to 4 hours enhanced the phosphorylation of P65, which began at 0.5 hour, peaked at 1.5 hours, and restored to the normal level at 4 hours, and the level of P65 phosphorylation was about 6.6 times that in the untreated control group. The CoCl2 of 2 mmol/L decreased the cell viability of HaCaT cells in a time dependent manner, and a significant difference was observed in the viability of HaCaT cells between CoCl2-treated and untreated HaCaT cells at 2, 4, and 6 hours (P ＜ 0.05, 0.01, 0.01 ). The release of IL-6 and IL-8 from HaCaT cells was also promoted by CoCl2 treatment. The knockdown of P65 expression with siRNA markedly suppressed the CoCl2-induced cytotoxicity to and increase in the release of IL-6 and IL-8 from HaCaT cells,despite of an increment in cell viability by about 11%. Conclusion The phosphorylated P65 subunit mediates CoCl2-induced cytotoxicity and inflammatory injury to HaCaT cells.

Structure Elucidation of Product of β-1,3-Glucosyltransferase Encoded by wfgD Gene in Escherichia Coli O152 Using Mass Spectrometry / 分析化学

The O152 antigens of Escherichia coli contains a Glc-β-1,3-GlcNAc linkage within the repeating unit. The wfgD gene in E. coli O152 O antigen gene cluster had been demonstrated utilizing NMR technique to encode a glucosyltransferase which is responsible for the synthesis of Glc-β-1,3-GlcNAc linkage. In this study, a synthetic substrate analog of the natural acceptor substrate undecaprenol-pyrophosphate-lipid [GlcNAc-α-PO_3-PO_3-(CH_2)_(11))-O-phenyl]) was used as an acceptor and UDP-Glc as a donor substrate, and electrospray ionization tandem mass spectrometry(ESI-MS-MS) was used for the detailed structural characte-)rization) of the enzyme product. A systematic study was conducted on product to allow rationalization of the fragmentation) processes. The major fragments observed in the ESI-MS-MS spectra result from cleavage of glycosidic) bond and diphosphate moiety. The fragment originating from the nonreducing end of the product yields information on sequence). Cross-ring cleavages, which are very informative of the linkages of the monosaccharide residues constituting) the product, and "internal" cleavage ions which are derived from elimination of substituents from around) the pyranose ring, were also observed. This extensive fragmentation was shown that the expected Glc-β-1,3-GlcNAc linkage in the product, confirming that wfgD is in the form of UDP-Glc: GlcNAc-pyrophosphate-lipid β-1,3-glucosyltransferase.)

Protective effect of N-acetyl cysteine against chemical hypoxia-induced injury to an immortal human skin keratinocyte line HaCaT / 中华皮肤科杂志

Objective To estimate the influences of N-acetyl cysteine (NAC) on a chemical hypoxiamimetic agent CoCl2 induced-injury to, and expressions of inflammatory factors by, an immortal human skin keratinocyte line HaCaT. Methods HaCaT cells were treated with CoCl2 of 2000 μmol/L for 4 hours to set up a chemical hypoxia-induced cell model of skin injury. NAC of various concentrations ( 1000, 2000, 3000 μmol/L)was used to pretreat HaCaT cells for 2 hours prior to the establishment of cell model. After these treatments,cell viability was detected by cell counting kit 8 (CCK-8), the levels of interleukin 6 and 8 (IL-6 and -8) and tumor necrosis factor α (TNF-α) in culture supernatant by ELISA kits, mitochondrial membrane potential (MMP) by rhodamine 123 (Rh123) staining and photofluorography, intracellular reduced glutathione (GSH)content by glutathione detection kit. Results An obvious decline was observed in HaCaT cell viability after pretreatment with various concentrations of NAC for 2 hours. The treatment with CoCl2 of 2000 μmol/L for 4 hours induced an elevation in the supernatant levels of IL-6, IL-8 and TNF-α and a decrease in GSH content and MMP, while the pretreatment with NAC for 2 hours retarded the CoCl2-induced increase in IL-6 and IL-8 levels as well as decrease in GSH content and MMP. Conclusion The reactive oxygen species (ROS) scavenger NAC can protect against CoCl2-induced injury to and inflammatory reaction in HaCaT cells, which may be associated with a decrement in oxidative stress.