ObjectiveTo investigate the inhibitory effect of peroxisome proliferator-activated receptor-?(PPAR?) agonist on mesangial cell(MC) proliferation and extracellular matrix expression induced by angiotensin Ⅱ(Ang Ⅱ).MethodsThe incorporation of 3H-thymidine(3H-TdR) and cell count were used as the measurement of MC proliferation.MC cell-cycle was analyzed by flow cytometry.Mouse primary MC was treated with various concentration of Ang Ⅱ(1,10,100 nmol/L) in the presence or Absence of N-acytosistin(NAC) or rosiglitazone.Transforming growth factor-?1(TGF-?1),plasminogen activator inhibitor-1(PAI-1),and fibronectin(FN) mRNA expression were determined by real time-PCR.Reactive oxygen species(ROS) production was measured by 2,7-dichlorofluorescein diacetate(DCFDA) fluorescence.Results1.One hundred nmol/L Ang Ⅱ increased 3H-TdR incorporation and cell number by 2.14 and 2.32 fold,respectively.Ang Ⅱ-induced MC proliferation was inhibited by PPAR? agonist rosiglitazone with dose-dependent manner in mouse MC.2.One hundred nmol/L Ang Ⅱ stimulation for 24 h induced 48% MC processed to S and G2/M phase.Rosiglitazone significantly blocked Ang Ⅱ increased cell number in S and G2/M phase.3.Rosiglitazone reduced Ang Ⅱ-induced TGF-?1,PAI-1,and FN mRNA expression with dose-dependent manner.4.One hundred nmol/L Ang Ⅱ stimulation for 60 min increased ROS production by 3.85 folds.Rosiglitazone significantly inhibited Ang Ⅱ-induced ROS production.Ten ?mol/L rosiglitazone almost completely blocked Ang Ⅱ-induced ROS production.ConclusionPPAR? agonist rosiglitazone could block Ang Ⅱ-induced MC proliferation and extracellular matrix expression via inhibition of ROS production.

Arsenic ; toxicity ; Arsenic Poisoning ; Ecotoxicology

Objective To investigate the DNA methylation feature and DNA methylation regulation to its transcription and expression of O6-methylguanine-DNA methyltransferase gene (MGMT) in NaAsO2-treated HaCaT cells. Methods HaCaT cells were treated 72 hours at intervals and repeatedly by 3.13, 6.25,12.50, and 25.00 μmol/L NaAsO2, MGMT gene promoter region was amplified in the transcription initiation site - 329 - + 93 region by bisulfate-sequencing polymerase chain reaction (BSP), the mRNA transcription and the protein expression of MGMT was detected by real-time quantitative PCR and Western blotting. NaAsO2-untreated HaCaT cell was set as a blank control, and human epidermal squamous carcinoma cell strain A431 was set as a positive control. Results Among the groups of HaCaT cells treated with 3.13, 6.25, 12.50 and 25.00 μmol/L NaAsO2, the positive rates of the DNA methylation of promoter region in MGMT gene were 0.63%(l/160), 6.25% (10/160), 10.63%( 17/160) and 18.75% (30/160), respectively, and methylated CpG sites were mainly located in - 249--146 region relative to transcription start site. There was no DNA methylation in the blank control. There were significant differences between the blank control and the NaAsO2-treated cells (x2 = 76.687, P< 0.05). Average levels of MGMT mRNA were 1.518 31 ± 0.180 54, 1.425 22 ± 0.180 39, 1.014 54 ± 0.096 79 and 0.887 72 ± 0.020 00, respectively among the groups of HaCaT cells treated with 3.13, 6.25, 12.50 and 25.00 μmol/L NaAsO2, compared with the blank control cells(1.198 29 ± 0.159 97), there were significant differences(F = 37.359, P < 0.05). Average levels of MGMT protein were 1.174 47 ± 0.064 75, 0.848 83 ± 0.057 01, 0.471 63 ± 0.023 34 and 0.240 34 ± 0.014 43, respectively among the groups of HaCaT cells treated with 3.13, 6.25, 12.50 and 25.00 μmol/L NaAsO2, compared with the blank control cells (1.066 19 ± 0.061 24), there were significant differences(F = 20.687, P < 0.05). Conclusions Arsenic can cause CpC island hypermethylation in the promoter region of MGMT gene, which results in inhibited MGMT mRNA transcription and protein expression. It might be one of the important mechanisms of arsenic-induced skin lesion.

Objective To investigate the effect of NaAsO2 on the binding levels of methyl CpG binding protein 2(MeCP2),DNA methyltransferase 1 (DNMT1) and histone deacetylase 1(HDAC1) to the hypermethylation promoter region of MGMT gene in HaCaT cells,in order to provide a basis to deepen the interpretation of the role of arsenic poisoning mechanism.Methods HaCaT cells were treated repeatedly and interval with different concentrations of NaAsO2(3.13,6.25,12.50,25.00 μnol/L,respectively) for 72 h.Untreated HaCaT was used as blank control group and human epidermal squamous carcinoma cell line(A431 cells) as positive control group.The binding levels to the two transcription regulatory regions(ChIP1,ChIP2) and to the coding region(ChIP3) of MGMT 8ene were detected by chromatin immuno-precipitation combined with quantitative PCR.Results The differences of binding levels of MeCP2,DNMT1 and HDAC1 to ChIP1 and ChIP2 in each group were significant (F=7.387,84.634,78.442 and 19.263,69.649,26.546,all P ＜ 0.05).The binding levels of MeCP2,DNMT1 and HDAC1 to ChIP1 and ChIP2 in each NaAsO2 exposed group[3.13 μmol/L NaAsO2 exposed group:(136.00 ±16.97)％,(145.00 ± 2.83)％,(88.50 ± 19.09)％ and (106.50 ± 37.48)％,(112.34 ± 8.73)％,(59.71 ± 8.49)％;6.25 μmol/L NaAsO2 exposed group:(130.00 ± 42.43)％,(154.50 ± 4.95)％,(101.00 ± 1.27)％ and (88.50 ±3.54)％,(134.32 ± 2.82)％,(102.75 ± 19.91)％ ; 12.50 μmol/L NaAsO2 exposed group:(141.50 ± 23.33)％,(161.50 ± 7.78)％,(125.00 ± 11.31)％ and (119.50 ± 24.75)％,(171.59 ± 3.54)％,(167.61 ± 10.61)％; 25.00μmol/L NaAsO2 exposed group:(134.50 ± 43.13)％,(472.50+ 50.20)％,(383.50 ± 30.41)％ and (180.09 ±12.73)％,(348.50 ± 27.58)％,(158.45 ± 12.02)％] were higher than that in the blank control group[(51.50 ±9.19)％,(82.00 ± 12.73)％,(25.03 ± 2.91)％ and (37.02 ± 4.24)％,(91.56 ± 26.16)％,(19.09 ± 2.90)％,all P ＜ 0.05].The differences of binding levels of MeCP2 to ChIP3 in each group were not significant(F =1.670,P ＞0.05),but the differences of binding levels of DNMT1 and HDAC1 to ChIP3 were significant (F =4.404,9.863,all P ＜ 0.05),and only the binding levels in the 25.00 μmol/L NaAsO2 exposed group [(615.85 ± 29.63)％,(306.09 ± 59.40)％] were higher than that in the blank control group[(99.70 ± 12.02)％,(92.45 ± 48.79)％,all P ＜ 0.05].Conclusions MeCP2 can bind to the methylated MGMT gene transcriptional regulatory regions which are induced by arsenic and leads to histone deacetylation by the recruitment of DNMT1 and HDAC1 and,meanwhile,DNMT1 can bind to the coding region of MGMT gene to recruit HDAC1 in a methyl DNA binding protein(MBD) independence manner and media MGMT gene silencing through the chromatin remodeling way,which might be the early molecular events of arsenic poisoning.

AIM:To observe the effects of Dickkopf-3 ( Dkk-3 ) in diabetic retinopathy ( DR ) circulating blood in patients with the expression level, the Dkk - 3 development changes in the diabetic retinopathy of significance in the diagnosis of early DR.
● METHODS: Eighty - five type 2 diabetic patients, included the non - proliferative diabetic retinopathy ( NPDR ) 23 patients, proliferative diabetic retinopathy, proliferative DR ( PDR ) in patients with 30 and non-diabetic retinopathy ( NDR ) with 32 cases. The same period of healthy physical examination was selected as control group ( 80 cases ) . Serum samples were collected, and the relative expression level of Dkk-3 was detected by enzyme - linked immunosorbent assay ( ELlSA) double antibody sandwich assay. The statistical differences were compared between groups.
●RESULTS: The plasma level of Dkk - 3 ( 430. 16 ± 198. 11pg/mL) in DR patients was significantly lower than that in healthy control group (627. 48±294. 45 pg/mL; P<0. 05 ) and NDR patients ( 601. 99 ± 194. 16 pg/mL; P<0. 05). While there was no significant difference in Dkk-3 level between NDR and healthy control group ( P =0. 729). The level of PDR in patients with Dkk-3 (396. 38± 185. 59 pg/mL) was lower than that of NPDR (538. 82 ± 187. 20 pg/mL;P=0. 002).
●CONCLUSION:The decrease of Dkk-3 level may be related to the occurrence and development of diabetic retinopathy, and there is a significant correlation with PDR. Circulating blood Dkk - 3 protein in diabetic retinopathy has a certain differential efficacy, it is likely to become diabetic retinopathy patients peripheral blood test indicators.

Objective To investigate the distribution of pathogenic bacteria,drug sensitivity,and the relationship between drug sensitivity and Escherichia coli(E.coli) induced enzymes in childhood diarrhea in the last 2 years in Chongqing area,so as to provide important evidence for pediatric clinical therapy.Methods Thirty-one E.coli induced enzymes,extended spectrum ?-laetamases(ESBLs),cephalosporinase(AmpC)detected in different phenotype methods,and drug sensitivity was measured in paper strip method,and the specimens were collected from children′s hospital affiliated to chongqing university of medical sciences from Jan.2005 to Dec.2006 were determined.Among the total,there were 18 enteropathogeic E.coli(EPEC) strains,8 enterotoxigenic E.coli(ETEC) strains and 5 enteroinvasive E.coli(EIEC) strains.In addition,drug resistance tests by paper strip included chloramphenicol(CHL),amikacin(AMK),gentamicin(GEN),norfloxacin(NOF),ciproflocacin(CIP),cefazolin(CEZ),cefoperazone(CPZ),ceftriaxone(CRO),ceftazidime(CAZ),cefotacime(CTX),cefepime(FEP),imipenem(IPM).SPSS 12.0 software was used to analyze the data.Results Three point two percent of the 31 E.coli were drug resistant to IPM,and 35.5%,38.7% to NOF,CIP individually,but more than 60% to AMK,GEN,even more than 67.7% towards cephalosporin(except ceftazidime and cefepime);the gross enzyme-produced rate was 87.1%,rate of single ESBLs,AmpC,and induction of both enzymes simultaneously presented 64.5%,6.5%,16.1% respectively;and there was marked difference in drug resistance when bacteria that produced single AmpC versus bacteria that produced single ESBLs or that produced both ESBLs and AmpC(Pa﹤0.05).Conclusions The relationships among enzyme′s quantity,sort and bacterial resistance are different.These data show E.coli infected by bacterial diarrhea children in Chongqing due to a high rate of induced enzymes,and their drug resistance vary according to the state of induced enzymes.

Objective To explore the inhibitory effect of rosiglitazone of peroxisome proliferator-activated receptor-?(PPAR?) agonist on aldosterone-induced mesangial cell(MC) proliferation.Methods Mouse primary MC were cultured and treated with aldosterone(100 nmol/L) in the presence or absence of rosiglitazone(1.0,2.5,5.0,10.0 ?mol/L).The incorporation of 3H-thymidine(3H-TdR) and cell count were used as the measure of MC proliferation.Cyclin D1 and cyclin A expression,PI3K and Akt phosphorylation were determined by Western blot analysis.Results 1.Aldosterone induced MC proliferation,as assessed by 3H-TdR incorporation and cell number,which were increased by 2.46-and 2.14-fold,respectively,in aldosterone-treated cells.Aldosterone-induced MC proliferation was inhibited by PPAR? agonist rosiglitazone in dose-dependent manner in mouse MC.2.Aldosterone induced cyclin D1 and cyclin A expression.Rosiglitazone reduced aldosterone-induced cyclin D1 and cyclin A expression in dose-dependent manner.3.Aldosterone induced PI3K/Akt activation in dose-dependent manner,incubation with 100 nmol/L aldosterone for 60 min,phosphorylation PI3K and Akt expression increased by above 3.0-fold.4.PI3K inhibitor LY294002 and Akt inhibitor significantly inhibited aldosterone-induced cyclin D1 and cyclin A expression.5.Rosiglitazone significantly inhibited aldosterone-induced PI3K/Akt activation,10 ?mol/L rosiglitazone almost completely blocked aldosterone-induced PI3K/Akt activation.Conclusion Rosiglitazone can block aldosterone-induced MC proliferation via inhibition of PI3K/Akt activation.

Objective To investigate the effect of c-Jun N-terminal kinase(JNK) specific inhibitor SP600125 on Angiotensin Ⅱ(AngⅡ)-induced transforming growth factor-?1(TGF-?1) and fibronectin (FN) expression in human mesangial cells (MC).Methods Human MC were isolated and cultured in vitro and were treated with AngⅡ in the presence or absence of JNK specific inhibitor SP600125.The protein was isolated or the supernate of medium was collected at the end of experiment.JNK,extracellular signal-regulated kinase(ERK1/2),and p38 mitogen-activated protein kinase(MAPK) activity were determined by Western blot method.TGF-?1 and FN were determined by enzyme linked immunosorbent assay(ELISA).Results SP600125 inhibited AngⅡ-induced Ser63 phosphorylation of c-Jun in a concentration-dependent manner,and JNK activity was reduced by 75% at 10 ?mol/L and by 90% at 20 ?mol/L.SP600125 had no effect on AngⅡ-induced ERK1/2 and p38 activity.TGF-?1 and FN protein were constitutively produced in MC,and production was significantly stimulated for 8 to 48 h after addition of AngⅡ.Preincubation of cells with SP600125(20 ?mol/L) significantly inhibited AngⅡ-induced TGF-?1 and FN production during this time period.SP600125 inhibited AngⅡ-induced production of TGF-?1 and FN in a concentration-dependent manner.Conclusion SP600125 inhibited AngⅡ-induced JNK activation and TGF-?1 and FN expression in human MC and may serve as the novel approach for the treatment of patients with chronic kidney disease.

Objective To study the transcription and expression of excision repair cross complementing 1(ERCC1) in the peripheral blood and the skin tissue in coal-burning borne endemic arsenism, and to explore the role of arsenism in its pathogenic or carcinogenesis mechanism. Methods According to "Endemic arsenism diagnostic criteria" (WS/T 211-2001), 110 arsenism patients were chosen as case group in Xingren county,Guizhou province and they were divided into 3 groups according to their hnir arsenic: ＜ 2(31 cases),2 ～＜ 4(31 cases),≥4 mg/kg(48 cases), respectively. Another 36 healthy residents about 13 km away from the endemic area were chosen as healthy control group. Under the principle of informed consent, hair samples were collected for arsenic analysis by Ag-DDC and blood samples were collected to determine mRNA expression levels of ERCCI by real-time fluorescence quantitative PCR. At the same time, skin tissue samples were collected from the voluntary surgical treatment of 62 patients with endemic arsenism as case group which were divided into 3 groups according to their hair arsenic: ＜ 2(16 cases), 2 ～＜ 4(20 cases) and ≥4 mg/kg(26 cases), respectively, and these patients were also divided into general pathological changes (32 cases), precancerous (19 cases) and cancerous groups( 11cases), respectively, according to their skin pathologic diagnosis of skin lesions. Another 13 cases pathologically normal without skin cancer surgery from a certain hospital were chosen as control group. Skin samples were collected to detect the ERCC1 protein by immunohistochemical method. Results The mRNA levels of ERCC1 were 0.7156(0.2158 ～ 1.2405),0.5772(0.0843 ～ 1.1234) and 0.5490(0.1895 ～ 0.8431 ), respectively, among ＜ 2, 2 ～＜ 4and ≥4 mg/kg groups, which were lower than the mRNA levels of ERCC1 in the control group[1.5128(1.0000 ～2.1295)], and the difference was statistically significant(all P ＜ 0.05). The expression rate of ERCC1 protein were 87.5%, 80.0% and 77.0%, respectively, among ＜ 2, 2 ～＜ 4 and ≥4 mg/kg groups. The expression rate of ERCC1 protein in 2 ～＜ 4 and ≥4 mg/kg groups were lower than the rate in the control group(100.0%), and the difference was statistically significant (all P ＜ 0.05). The expression rate of ERCC1 protein were 84.4%, 79.0%and 72.8%, respectively, among general pathological changes, precancerous and cancerous groups compared with the control group( 100.0% ), and the difference was statistically significant(all P ＜ 0.05). Conclusions Arsenic from coal-burning can lead to abnormal ERCC1 gene transcription and protein expression, which may inhibit DNA repair through influencing the removal of damaged DNA and promoting the incidence of arsenism development and even skin carcinogenesis.

ObjectiveTo investigate glutathione S-transferase GSTO 1 Glu155△Glu genetic polymorphism and risks of arsenic poisoning caused by coal-burning in Guizhou.Methods GSTO1 Glu155 △Glu gene polymorphism was analyzed by polymerase chain reaction-with confronting two-pair primers among one hundred and thirty arsenic poisoning patients and one hundred and thirty healthy controls.The results were verified by DNA sequencing.The association between different genotypes and arsenic poisoning was analyzed by unconditional Logistic regression model.ResultsThe results of Glu/Glu and Glu/△Glu genotype detected by this method were consistent with those of DNA sequencing.The frequencies of GSTO1 Glu/Glu genotype and Glu/△Glu genotype were 94.85％(92/97) and 5.15％(5/97) in the patients,99.15％(117/118) and 0.85％(1/118) in the controls,respectively.The difference was statistically significant(x2 =3.896,P ＜ 0.05).△Glu/△Glu genotype was not found in both patients and controls.After age and sex adjusting,GSTO1 Glu155 △Glu polymorphism was found to be a risk factor of arsenic poisoning [odds ratio (OR) =1.85,95％ confidence interval (CI):1.39 - 17.48].ConclusionsThe study finds that GSTO1 Glu 155 △ Glu polymorphism is associated with risk of arsenic poisoning.The relationship between them should be further studied through increasing sample size.