Role of NRF2 signaling pathway in trichloroethylene-induced oxidative stress in HepG2 cells / 中国职业医学

OBJECTIVE: To investigate the role of nuclear factor erythroid-2-related factor 2(NRF2) signaling pathway in trichloroethylene(TCE) induced oxidative stress in human liver cancer HepG2 cells. METHODS: HepG2 cells in the exponential growth phase were randomly divided into control group and low-, medium-and high-dose groups, and the cells were stimulated with TCE at the final concentrations of 0, 2, 4 or 8 mmol/L respectively for 24 hours. After TCE exposure, the cells were collected. The activity of superoxide dismutase(SOD) was measured by 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulphenyl)-2 h-tetrazole monosodium salt method.The activities of catalase(CAT) and glutathione peroxidase(GSH-Px) were detected by enzymatic method. The level of malondialdehyde(MDA) was detected by thiobarbituric acid method. The level of 8-hydroxydeoxyguanosine(8-OHDG) was detected by enzyme-linked immunosorbent assay. The mRNA expression of NRF2, heme oxygenase(HO1), glutamate-cysteine ligase catalytic subunit(GCLC), NAD(P) quinone oxidoreductase 1(NQO1) were detected by real-time polymerase chain reaction and the protein expression of NRF2, HO1, GCLC, NQO1 were detected by Western blotting. RESULTS: The activity of CAT in HepG2 cells decreased in the 3 doses drug exposure groups(all P<0.05). The activity of GSH-Px increased(all P<0.05), while the level of MDA in HepG2 cells decreased in low-dose group compared with the control group(P<0.05). There was no statistical significance in SOD activity and 8-OHDG level of HepG2 cells among these 4 groups(all P>0.05). The mRNA and protein relative expression of NRF2 and GCLC in HepG2 cells decreased in the low-and medium-dose groups(all P<0.05) compared with the control group. The mRNA relative expression of HO1 decreased(all P<0.05). The HO1 protein relative expression of HepG2 cells increased in low-dose group compared with the control group(P<0.05). The mRNA and protein relative expression of NQO1 in low-dose group increased(both P<0.05). The protein relative expression of HO1 in HepG2 cells in medium-dose group was lower than that in control group(P<0.05).The mRNA and protein relative expression levels of NRF2 and NQO1 increased in HepG2 cells of high-dose group(all P<0.05) and the mRNA relative expression of HO1 increased in HepG2 cells of high-dose group(all P<0.05) compared with the other 3 groups. CONCLUSION: The low and medium dose TCE stimulation can cause oxidative stress in HepG2 cells and decrease the antioxidant enzyme activity. The high dose TCE stimulation to HepG2 cells can activate NRF2 signaling pathway, thus upregulating the expression of downstream antioxidant enzymes HO1, GCLC and NQO1, and relieving the oxidative damage caused by TCE.

A retrospective cohort study of the long-term effects of endoscopic submucosal dissection in treating early gastrointestinal cancer or precancerous lesions / 中国内镜杂志

Objective A retrospective cohort study was carried out to observe the long-term effect of ESD in treating early gastrointestinal cancer or precancerous lesions. Methods The clinical and follow-up data of 73 patients were collected. Kaplan-Meier, Log-rank and Breslow test and Cox's proportional hazards regression model were used to analyze the data. Results The median survival time in the gastric and colo-rectal early cancer or precancerous lesions is longer than 65 months in our study, respectively. For esophagus, the median survival time was 44.5 months; the disease free survival time (DFS) after ESD was significantly reduced in the esophagus, compared to the stomach and colo-rectum (χ2 = 12.61, P = 0.000; χ2 = 7.09, P = 0.008); the degree of atypia (or infiltration), and lesion size were considered to be two factors to influence the DFS after ESD (P = 0.027, OR

A comparative study of narrow-band imaging (NBI) with routine endoscopy and NBI with magnifying endoscopy for the diagnosis of colorectal neoplasia / 中华消化内镜杂志

Objective To compare the diagnostic efficacies of narrow-band imaging (NBI) in distinguishing neoplastic from non-neoplastic colorectal lesions with routine endoscopy and with magnifying endoscopy. Methods Patients with colorectal lesions detected by NBI from September 2008 to February 2010 were enrolled in the study. These lesions were classified by pit pattern and capillary pattern, which was then assessed by reference to histopathology. Results A total of 100 patients with colorectal lesions were enrolled, and the lesions were observed by NBI with ordinary endoscopy (n =64) and NBI with magnifying endoscopy (n =36), respectively, and 7 cases (5 in NBI with ordinary endoscopy and 2 in NBI with magnifying endoscopy) which did not meet the diagnostic criteria were excluded. The overall diagnostic accuracy of NBI endoscopy in distinguishing neoplastic from non-neoplastic colorectal lesions was 91.4% ( 85/93 ), in which NBI with ordinary endoscopy and magnifying endoscopy was 89. 8% (53/59) and 94. 1% (32/34),respectively, with both significantly higher than that of conventional colonoscopy reported in the literature (79. 1% ) (P ＜ 0. 05 ). However, no significant difference was detected between 2 methods ( P ＞ 0. 05 ).Conclusion Similar with NBI magnifying endoscopy, NBI endoscopy without high magnification may also be useful to distinguish neoplastic from non-neoplastic colorectal lesions.