Effects of trichloroethylene on hepatotoxicity in cytochrome 2E1-silenced hepatocytes / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To prepare cytochrome (CYP)2E1-silenced hepatocytes by lentivirus-mediated RNA interference technology and to investigate the hepatotoxicity of trichloroethylene (TCE) in CYP2E1-silenced hepatocytes.</p><p><b>METHODS</b>Short hairpin RNA fragments were designed and synthesized and were then ligated into the lentiviral vector; single colonies were screened; the plasmid was extracted after PCR and sequence identification and then transferred into L02 hepatocytes; the CYP2E1-silenced hepatocytes were selected; real-time quantitative PCR and Western blot were used to evaluate the interference effects. The obtained CYP2E1-silenced hepatocytes, as well as normal L02 hepatocytes, were treated with TCE (0, 0.25, 0.50, 1.00, 2.00, and 4.00 mmol/L). The cell viability and half maximal inhibitory concentration (IC50) of TCE were measured; the apoptotic rate of cells was measured by flow cytometry; the mRNA expression levels of apoptosis genes and oncogenes were measured by real-time quantitative PCR.</p><p><b>RESULTS</b>The IC50s of TCE for L02 hepatocytes and CYP2E1-silenced hepatocytes were 15.1 mmol/L and 23.6 mmol/L, respectively. The apoptotic rate increased as the dose of TCE rose in the two types of cells; the CYP2E1-silenced hepatocytes hada significantly lower apoptotic rate than L02 hepatocytes when they were exposed to 2.0 and 4.0 mmol/L TCE (P < 0.05 or P < 0.01). The mRNA expression level of bcl-2 (anti-apoptosis gene) in CYP2E1-silenced hepatocytes was 15% ∼ 60% higher than that in L02 hepatocytes (P < 0.01), while the mRNA expression levels of caspase-3 and caspase-9 (apoptosis genes) in CYP2E1-silenced hepatocytes were 30% ∼ 60% lower than those in L02 hepatocytes (P < 0.01). The mRNA expression level of p53 (cancer suppressor gene) in CYP2E1-silenced hepatocytes was 81 - 278% higher than that in L02 hepatocytes (P < 0.01), while the mRNA expression levels of c-fos and k-ras (oncogenes) in CYP2E1-silenced hepatocytes were 20-68% lower than those in L02 hepatocytes (P < 0.01).</p><p><b>CONCLUSION</b>CYP2E1-silenced cells can be successfully prepared by lentivirus-mediated RNA interference technology. Silencing CYP2E1 gene can reduce the hepatotoxicity of TCE and inhibit the expression of some apoptosis genes and oncogenes, suggesting that CYP2E1 gene plays an important role in TCE metabolism and is related to the hepatotoxicity of TCE.</p>

Study on sperm damage caused by trichloroethylene in male rats / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study in vitro sperm damage caused by trichloroethylene in male rats.</p><p><b>METHODS</b>Sperms of Sprague-Dawley (SD) rats were collected 4 hours after being contaminated by trichloroethylene of 0, 2, 4, 6, 8, and 10 mmol/L in vitro. Giemsa staining was performed to observe the morphological changes of sperms, and flow cytometer was used to detect the changes in mitochondrial membrane potential.</p><p><b>RESULTS</b>The sperm motilities in 6, 8, and 10 mmol/L trichloroethylene groups decreased significantly compared with that in control group (P <0.01); the sperm aberration rates in 8 and 10 mmol/L trichloroethylene groups were significantly higher than that in control group (P<0.01). With the increase in exposure dose, the proportion of sperms with reduced mitochondrial membrane potential increased, and there were significant differences in sperm apoptosis rate between the 4, 6, 8, and 10 mmol/L trichloroethylene groups and control group (P<0.01).</p><p><b>CONCLUSION</b>In vitro exposure to trichloroethylene can reduce sperm motility and increase the aberration rate and apoptosis rate of sperms in male SD rats.</p>

Identification and Characterization of a Lactococcus lactis Strain with the Distinctive Antimicrobial Activity Against Gram-negative Bacteria and a Yeast / 微生物学通报

Using the Gram-positive Staphylococcus aureus as the indictor bacterium,fourteen antibacterial strains were initially obtained by the bilayer-media screening method from the raw milk samples,and one isolate was found to exhibit the higher antibacterial activity against the indicator. This isolate was further studied on its individual and cultural morphology features,partial physiological and biochemical reaction activities,G+C content,the sequence features of the 16S rDNA and the species-specific N-acetylmuraminidase gene(acmA) ,consequently,it was identified as the Lactococcus lactis subsp. lactis strain,named as MB191. An evaluation of the antimicrobial spectra of MB191 was subsequently performed,it showed the remarkable activities against not only the tested Gram-positive bacteria,but also several Gram-negative bacteria including Pseudomonas syringae and P. fluorescens,as well as the yeast Debaryomyces hansenii,which was a distinctive feature that was not reported prior to this study.