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Objective:To evaluate the correlation between endemic arsenic poisoning and abnormal electrocardiogram (ECG).Methods:PubMed, Web of Science, Embase, China National Knowledge Infrastructure (CNKI), Wanfang data, VIP and other databases were used for literature retrieval, and epidemiological literatures related to abnormal ECG of endemic arsenic poisoning published in domestic and abroad were included in the study. The time limit was from the establishment of the database to December 1, 2020. RevMan 5.3 was used for Meta-analysis of binary variables. Random effect model was selected according to the results of heterogeneity, and odds ratio ( OR) was used as the effect index. Characteristic changes were found by subgroup analysis. Bias was published by funnel plot. Results:Nine articles were included in this Meta-analysis, with 6 articles in Chinese and 3 articles in English, respectively. The abnormal ECG changes included QTc prolongation, ST-T segment change, left axis deviation and arrhythmia. Finally, 1 975 cases were included in the exposure group, including 575 cases of abnormal ECG; 750 cases of control group, including 145 cases of abnormal ECG. Meta-analysis showed that the combined OR value [95% confidence interval ( CI)] of abnormal ECG changes was 4.41 (2.83 - 6.87), with statistical significance between the two groups ( Z = 6.56, P < 0.05); the results of subgroup analysis showed that the combined OR values (95% CI) of QTc prolongation, ST-T segment change, left axis deviation and arrhythmia were 12.30 (5.91 - 25.59), 2.74 (1.39 - 5.41), 2.93 (0.89 - 9.62) and 4.13 (2.38 - 7.17), respectively. Conclusions:Endemic arsenic poisoning may cause abnormal ECG. Prolongation of QTc caused by arsenic exposure may be the characteristic change of abnormal ECG.
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Objective:To observe the role of nuclear factor erythroid 2-related factor 2 (Nrf2) in regulating apoptosis during malignant transformation of human bronchial epithelial cells (HBE cells) induced by sodium arsenite (NaAsO 2). Methods:HBE cells were treated with 0.0 and 1.0 μmol/L NaAsO 2, which were control group and arsenic exposed group respectively. HBE cells were treated with 1.0 μmol/L NaAsO 2 for 43 passages to establish a malignant transformation model. The dynamic changes of indexes in different passages (0, 1st, 8th, 15th, 22nd, 29th, 36th, and 43rd) after exposure to NaAsO 2 were monitored, including the apoptosis rate detected by flow cytometry and apoptosis-related proteins and Nrf2 protein detected by Western blotting. Nrf2 siRNA was transfected into malignant transformed HBE cells (T-HBE cells) to silence Nrf2. The silencing effect of Nrf2 protein was verified. And, the apoptosis rate and apoptosis-related proteins were detected. Results:With the increase of arsenic exposure, the apoptosis rates of HBE cells decreased (0, 1, 8, 15, 22, 29, 36 and 43 passages were 0.370 ± 0.029, 0.443 ± 0.069, 0.357 ± 0.046, 0.330 ± 0.016, 0.273 ± 0.050, 0.160 ± 0.024, 0.110 ± 0.022, 0.097 ± 0.012, respectively, Ftrend = 22.981, P < 0.05). Compared with the 0 passage cells, the apoptosis rates of the 22nd, 29th, 36th and 43rd passages in the arsenite group were lower. The differences between them were statistically significant ( P < 0.05). With the increase of arsenic exposure, the expressions of pro-apoptotic proteins caspase-3, cleaved-caspase-3, C/EBP-homologous protein (CHOP) and B-cell lymphoma-2 (Bcl-2) associated X protein (Bax) showed downward trends ( Ftrend = 22.356, 3.738, 6.130, 8.061, P < 0.05), while the anti-apoptotic proteins myeloid cell leukemia 1 protein (Mcl-1) and Bcl-2 showed upward trends ( Ftrend = 58.201, 7.691, P < 0.05). Compared with the 0 passage and the control group of the same passage, from the 22nd passage of caspase-3, cleaved-caspase-3, from the 15th passage of CHOP, Mcl-1, and Bcl-2, from the 29th passage of Bax in the arsenite group, the differences of protein were statistically significant ( P < 0.05). However, there were no significant differences in caspase-8, cleaved-caspase-8, caspase-12 and cleaved-caspase-12 protein expressions in the arsenic group ( P > 0.05). Compared with the 0 passage and the control group of the same passage, from the 8th passage of Nrf2 proteins in the arsenite group, the differences of expressions were statistically significant ( P < 0.05). Compared with T-HBE cells transfected with Con siRNA (control), the apoptosis rate of T-HBE cells transfected with Nrf2 siRNA was higher ( P < 0.05). Compared with T-HBE cells transfected with Con siRNA, the expression levels of Nrf2, Bcl-2 and Mcl-1 in T-HBE cells transfected with Nrf2 siRNA were lower ( P < 0.05), while the expression levels of cleaved-caspase-3/caspase-3, caspase-3, cleaved-caspase-3, CHOP, and Bax were higher ( P < 0.05). Conclusion:Nrf2 may regulate mitochondrial apoptotic pathway through Bcl-2, Mcl-1 and Bax, and endoplasmic reticulum apoptotic pathway through CHOP, so as to inhibit the apoptosis of HBE cells and participate in the process of malignant transformation of HBE cells induced by NaAsO 2.
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Objective:To explore the role of nuclear transcription factor erythrocyte line-2p45 (NF-E2) related factor-2 (NRF2) on autophagy during malignant transformation of immortalized human keratinocytes (HaCaT) induced by sodium arsenite (NaAsO 2). Methods:Using cell culture methods, long-term cultured HaCaT cells in DMEM high-glucose medium containing 0.0 (control group) and 1.0 μmol/L NaAsO 2 (arsenic-exposed group) to the 35th generation were used to construct a cell malignant transformation model, and 0, 1, 7, 14, 21, 28 and 35th generation cells of control group and arsenic-exposed group were collected during establishment of cell malignant transformation model. The NRF2 siRNA, phosphatidylinositol-3-hydroxykinase (PI3K) inhibitor LY294002 and mammalian target of rapamycin (mTOR) inhibitor Rapamycin were used to treat the 35th generation of malignant transformed HaCaT cells in arsenic-exposed group (T-HaCaT). The protein expressions of NRF2, PI3K-protein kinase B (Akt)-mTOR signaling pathway related indicators PI3K, Akt, mTOR, phosphorylated (p)-PI3K, p-Akt, p-mTOR, autophagy-related proteins p62, Beclin1, microtubule-associated protein-1 light chain (LC)3Ⅰ, and LC3Ⅱof different generations HaCaT cells in control group and arsenic-exposed group, and T-HaCaT cells of each treatment group were determined by Western blotting. Results:There were significant differences in the NRF2 protein and the ratios of p-PI3K/PI3K, p-Akt/Akt and p-mTOR/mTOR between different generations HaCaT cells in arsenic-exposed group ( F = 9.371, 16.035, 15.932, 27.739, P < 0.05), and they were higher than NRF2 protein and ratio of p-mTOR/ mTOR of the same generation in control group ( P < 0.05). Compared with HaCaT cells of the same generation, the expressions of NRF2, p-PI3K, p-Akt, p-mTOR and p62 proteins in T-HaCaT cells were significantly higher, Beclin1 protein expression and the ratio of LC3Ⅱ/LC3Ⅰ were significantly lower ( P < 0.05). The NRF2 silenced T-HaCaT cells had higher expression of Beclin1 and the ratio of LC3Ⅱ/LC3Ⅰ, and lower expressions of NRF2, p-mTOR and p62 than the corresponding control siRNA (Con siRNA) group ( P < 0.05). The T-HaCaT cells in LY294002 treatment group had higher expression of Beclin1 and the ratio of LC3Ⅱ/LC3Ⅰ, and lower expressions of NRF2, p-PI3K, p-Akt and p-mTOR proteins than the corresponding non-treatment group ( P < 0.05). The T-HaCaT cells in Rapamycin treatment group had higher expression of Beclin1 and the ratio of LC3Ⅱ/LC3Ⅰ, and lower expression of p-mTOR protein than the corresponding non-treatment group ( P < 0.05). Conclusions:During the arsenic-induced malignant transformation of HaCaT cells, NRF2 can act as a downstream factor of PI3K-Akt and an upstream factor of mTOR in PI3K-Akt-mTOR signaling pathway, an important regulatory mechanism of autophagy. This abnormal expression of autophagy may eventually lead to malignant transformation of cells.
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With the deepening of the research on the "two sides" of arsenic from poison to medicine, arsenic has attracted extensive attention in affecting programmed cell death (PCD) and causing damage to a variety of organs. Recent studies have showed that reactive oxygen species (ROS) produced by intracellular arsenic metabolism is closely related to PCD induction. However, the specific mechanism is still unclear. In this paper, we have reviewed the main PCD forms, such as apoptosis, autophagy and necroptosis induced by arsenic via ROS and their possible mechanisms, in order to provide basic information for further research and prevention of arsenic toxicity, which is helpful for clinical development and utilization of arsenic in the treatment of tumors and related diseases.