With the oxidative damage model established in rat myocardial cells by hydrogen peroxide (H2O2), the expression of myocardin and nuclear factor erythroid 2-related factor 2 (Nrf2) during oxidative damage and effect of myocardin on Nrf2 were preliminarily explored. The expression of the target gene was increased or decreased by transfection of plasmid DNA or shRNA, respectively. Cell proliferation was detected by sulforhodamine B (SRB) assay. The expression of myocardin mRNA and Nrf2 mRNA was detected by Real-time PCR, and their protein levels were detected by Western blot. The results showed that oxidative damage was induced by H2O2 with an optimized incubation condition of 200 μmol/L H2O2 for 24 hours. H2O2 inhibited expression of myocardin in mRNA and protein levels, and increased expression of Nrf2 in mRNA and protein levels. The overexpression of myocardin or the knockdown of Nrf2 significantly decreased cell viability compared with the control group, while the knockdown of myocardin or the overexpression of Nrf2 significantly increased cell viability. The overexpression of myocardin significantly down-regulated the expression of Nrf2 in mRNA and protein levels, while the knockdown of myocardin dramatically up-regulated the expression of Nrf2. Thus, it is deduced that myocardin may inhibit cell proliferation and Nrf2 may promote cell proliferation. Oxidative damage induced by H2O2 in rat myocardial cell might activate Nrf2-related signaling pathway through down-regulation of myocardin.
ObjectiveTo investigate the disinfection effect of dry-fogging hydrogen peroxide (DFHP) on ambulance inner surfaces.MethodsThis study was carried out using simulated field test and field test from October to December 2018. In the simulated field test, the carriers with Geobacillus stearothemopilus (ATCC12980) spores were placed in 6 places in the ambulance, and disinfected for 60 minutes with DFHP of 0.38–0.72 g/m3. The carriers were cultured for up to 7 days to observe whether the bacteria were eliminated. Before and after the DFHP disinfection, the microbial sampling of the surface in the ambulance was carried out, and the colonies were counted after the cultivation.ResultsThe eliminating rate of the bacteria carriers on the uncovered surface was 100% (20/20), and that of the covered surface was 10% (1/10). The pass rate of microbial sampling was 100% (26/26).ConclusionsThe DFHP had a significant decontamination effect on the ambulance inner uncovered surfaces. The DFHP equipment is automated and their disinfecting quality is consistent, therefore it is suitable for the disinfection of ambulance inner surfaces. But the limitation of disinfection effect on covered surfaces should be avoided.
Objective To explore the role of hydrogen peroxide (H2O2) in inducing chronic oxidative stress in microglia aging. Methods BV2 microglia purchased from ATCC in less than 10 generations were treated with 0, 50, 100, 200 μmol/L H2O2 at different concentrations. According to the concentration of H2O2 used, the BV2 microglia were divided into a control group and H2O2 -50 μmol/L Group, H2O2 -100 μmol/L Group, H2O2 -200 μmol/L Group. Cell proliferation was measured by CCK8 cell proliferation assay. Age-related β-galactosidase (SA-β-gal) staining assay, and expression of age-related cyclin molecules p16, p21, p53 and senescence sssociated secretory phenotype interleukin 1 beta (IL-1β), transforming growth factor-β (TGF-β) and matrix metalloprotein 9 (MMP9) detected by quantitative real-time polymerase chain reaction were used to measure celluar senescence. Results During the induction process, H2O2-200 μmol/L caused significant damage to BV2 microglia, therefore no subsequent testing was conducted. Finally, the control group, H2O2-50 μmol/L group and H2O2-100 μmol/L group cells were collected. The differences in cell survival rate (F=46.176, P<0.001) and positive rate of SA-β-gal staining (F=553.1, P<0.001) among the three groups were statistically significant. The cell survival rate of H2O2-50 μmol/L group had no significant change (P>0.05), while the cell survival rate of H2O2-100 μmol/L group decreased significantly (P<0.001). The positive rate of SA-β-gal staining in H2O2-50 μmol/L group and H2O2-100 μmol/L group was increased (P<0.001), and the positive rate of SA-β-gal staining in H2O2-100 μmol/L group was higher than that in H2O2-50 μmol/L group (P<0.001). The mRNA levels of senescence related cyclin molecules p16, p21 and p53 were up-regulated under the induction of 50, 100 μmol/L H2O2 (P<0.05), and the expressions of IL-1β, TGF-β and MMP9 of senescence associated secretory phenotype were increased (P<0.05). The increase of H2O2-50 μmol/L group was more obvious (P<0.05). Conclusion The aging model of BV2 microglia can be successfully established by inducing 8 d with 100 μmol/L H2O2, and the mechanism may be related to promoting the secretion of p16, p21, p53, IL-1β, TGF-β and MMP9.