RESUMEN
Objective @#To investigate the effects of the exposure of sludge from sewage treatment plants and microplastic extracted from sludge on the oxidative stress levels in zebrafish, so as to put insights into the research into the impact of sludge and microplastics on human health. @*Methods @#Adult wild AB zebrafish were exposed to five groups of sludge (0, 12.5, 25, 50 and 75 g/L) and four groups of microplastics extract from sludge (0, 240, 480, 960/L), with 24 zebrafish in each group. The color, activity and death of zebrafish were observed every day. The contents of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and malondialdehyde (MDA) were detected 0 h, 24 h, 48 h, 72 h, 96 h and 7 d post-exposure. A two-factor ANOVA was used to analyze the effects of different concentrations and time of exposure on the indicators above. @*Results @#Under 75 g/L sludge exposure, zebrafish began to show mortality at 72 h and all died after 7 d. The zebrafish in the other sludge groups and all microplastic groups had normal color and activity, and no mortality was observed. Sludge concentration interacted with exposure time to affect SOD, CAT, GSH and MDA (P<0.05). With increasing sludge concentration and exposure time, SOD decreased, MDA increased, CAT increased first and then decreased, GSH decreased first and then increased, and GSH continued to decrease since 24 h in the 75 g/L group. The microplastic concentration interacted with exposure time to affect SOD and GSH (P<0.05), but not CAT or MDA (P>0.05). With increasing microplastic concentration and exposure time, SOD and MDA increased, CAT increased first and then decreased, the GSH was slightly increased at 24 h and decreased after 72 h.@*Conclusion @#Both sludge and microplastics extracted from sludge can induce oxidative stress damage in zebrafish, and exposure time and concentration can interact to affect oxidative stress levels. The microplastics extracted from sludge have less effect on oxidative stress levels in zebrafish than sludge.
RESUMEN
Objective @#To investigate the role of hepatic long-chain non-coding RNA (lncRNA) H19 in key genes associated with glucose metabolism disorder induced by p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE).@*Methods@#Human embryonic liver CCC-HEL-1 cells were divided into the DMSO group, 0.1 μmol/L p,p′-DDE group, 1 μmol/L p,p′-DDE group, 10 μmol/L p,p′-DDE group, small interference RNA (siRNA)+DMSO group and siRNA+10 μmol/L p,p′-DDE group. The promoter region methylation, mRNA expression and protein expression of hepatocyte nuclear factor 4α (HNF4α), forkhead box transcription factor O1 (FoxO1) and insulin-like growth factor (IGF2) were detected in CCC-HEL-1 cells using the bisulfite method, real-time fluorescence quantitative PCR (qPCR) assay and BCA assay, respectively. The changes in H19 mRNA expression, the methylation of associated genes in the promoter region and transcriptional expression were compared in CCC-HEL-1 among groups.@*Results@#Exposure to p,p′-DDE alone at different doses resulted in an increase in H19 expression, and the H19 mRNA expression was higher in the 10 μmol/L p,p′-DDE group than in the DMSO group [(1.31±0.25) vs. (1.02±0.22); P<0.05]. Lower methylation of the HNF4α gene in the pro moter region [(38.59±32.77)% vs. (61.43±24.64)%; P<0.05] and higher HNF4α mRNA expression [(1.33±0.26) vs. (1.03±0.28); P<0.05] were detected in the 10 μmol/L p,p′-DDE group than in the DMSO group, while no significant differences were detected between the two groups in terms of the methylation of FoxO1 and IGF2 genes in the promoter region, FoxO1 and IGF2 mRNA and protein expression (P>0.05). Following siRNA-induced H19 knockdown, higher methylation of the HNF4α gene in the promoter region [(71.33±22.23)% vs. (38.59±32.78)%; P<0.05], lower HNF4α mRNA expression [(0.71±0.17) vs. (1.33±0.26); P<0.05], higher methylation of FoxO1 gene in the promoter region [(47.73±34.24)% vs. (25.09±25.35)%; P<0.05] and higher IGF2 mRNA [(1.39±0.25) vs. (0.80±0.20); P<0.05] were found in the siRNA+DMSO group than in the 10 μmol/L p,p′-DDE group, and higher IGF2 protein expression was detected in the siRNA+DMSO group than in the DMSO group [(1.03±0.11) vs. (0.74±0.12); P<0.05]. @*Conclusion@#Hepatic H19 may alter HNF4α, FoxO1 and IGF2 transcription and expression through mediating the methylation of genes in the promoter region, thereby playing a role in p,p′-DDE-induced glucose metabolism disorders.