Fluoride and arsenic exposure affects spatial memory and activates the ERK/CREB signaling pathway in offspring rats.

Fluoride and arsenic are inorganic contaminants that occur in the natural environment. Chronic fluoride and/or arsenic exposure can induce developmental neurotoxicity and negatively influence intelligence in children, although the underlying molecular mechanisms are poorly understood. This study explored the effects of fluoride and arsenic exposure in drinking water on spatial learning, memory and key protein expression in the ERK/CREB signaling pathway in hippocampal and cerebral cortex tissue in rat offspring. Pregnant rats were divided into four groups. Control rats drank tap water, while rats in the three exposure groups drank water with sodium fluoride (100mg/L), sodium arsenite (75mg/L), and a sodium fluoride (100mg/L) and sodium arsenite (75mg/L) combination during gestation and lactation. After weaning, rat pups drank the same solution as their mothers. Spatial learning and memory ability of pups at postnatal day 21 (PND21) and postnatal day 42 (PND42) were measured using a Morris water maze. ERK, phospho-ERK (p-ERK), CREB and phospho-CREB (p-CREB) protein expression in the hippocampus and cerebral cortex was detected using Western blot. Compared with the control pups, escape latencies increased in PND42 pups exposed to arsenic and co-exposed to fluoride and arsenic, and the short-term and long-term spatial memory ability declined in pups exposed to fluoride and arsenic, both alone and in combination. Compared with controls, ERK and p-ERK levels decreased in the hippocampus and cerebral cortex in pups exposed to combined fluoride and arsenic. CREB protein expression in the cerebral cortex decreased in pups exposed to fluoride, arsenic, and the fluoride and arsenic combination. p-CREB protein expression in both the hippocampus and cerebral cortex was decreased in pups exposed to fluoride and arsenic in combination compared to the control group. There were negative correlation between the proteins expression and escape latency periods in pups. These data indicate that exposure to fluoride and arsenic in early life stage changes ERK, p-ERK, CREB and p-CREB protein expression in the hippocampus and cerebral cortex of rat offspring at PND21 and PND 42, which may contribute to impaired neurodevelopment following exposure.

[Application of urinary proteomics in early diagnosis of bladder urothelial carcinoma].

OBJECTIVE: To investigate the difference in urinary proteome between patients with bladder urothelial carcinoma (BUC) and healthy volunteers and to provide a basis for the early diagnosis of BUC. METHODS: The urine samples from BUC patients and healthy volunteers (controls) were treated by 25% ethanol precipitation and two-dimensional gel electrophoresis (2-DE), and the obtained urinary proteins were subjected to Coomassie brilliant blue staining and analysis by PDQuest 8.0 (2-DE image analysis software); the differentially expressed proteins were sequenced by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry and identified using the Swiss-Prot database; the differential expression of these proteins was verified by western blot. RESULTS: High-resolution and high-reproducibility 2-DE images were obtained from the urine samples of BUC patients and controls, with 789 ± 18 and 762 ± 14 protein spots, respectively. Compared with the control group, the BUC grouP had significantly decreased expression of 6 protein spots and significantly increased expression of 11 protein spots. The mass spectrometry revealed five proteins with increased expression in the BUC group, including fibrinogen, lactate dehydrogenase B, apolipoprotein A1, clusterin, and haptoglobin, and the results were confirmed by western blot. CONCLUSION: There is significant difference in urinary proteome between BUC patients and healthy volunteers; the identification of differentially expressed proteins in urine lays the foundation for identifying potential molecular markers in early diagnosis of BUC.

[A case-control study on serum organochlorines residues, genetic polymorphisms of glutathione S-transferase T1 and the risks of breast cancer].

OBJECTIVE: To study the potential effect of gene-environment interaction between glutathione S-transferase T1 (GSTT1) and serum organochlorines residues on the risk of breast cancer in women, in China. METHODS: 70 newly diagnosed female breast cancer patients and 30 controls from September 2006 to October 2007 were interviewed using the same questionnaire to obtain information regarding exposure to those risks. Organochlorine residues level in serum was measured by gas chromatography (GC). Genotypes of GSTT1 polymorphisms were analyzed by multiplex allele-specific polymerase chain reaction (PCR). Interaction indexes (gamma) were calculated to determine the type of gene-environment interaction. RESULTS: After adjusting the confounding factors, results showed that interaction existed in genetic polymorphisms of GSTT1 and dichlorodiphenyltrichloroethane (DDT)/hexachlorocyclohexane (HCH) residues, with interaction indexes (gamma) value as 1.352 and 1.528. CONCLUSION: Genetic and environmental hazard factors had a co-effect on the development of breast cancer while genetic polymorphisms of GSTT1 and DDT/HCH expressed an interaction to breast cancer.

[Association between XRCC1 gene polymorphisms and DNA damage of workers exposed to formaldehyde].

OBJECTIVE: To investigate the association between polymorphisms of DNA repair gene XRCC1 and DNA damage in peripheral blood lymphocytes among workers exposed to formaldehyde. METHODS: One hundred and fifty-one workers exposed to formaldehyde from plywood factories and one hundred and twelve workers without occupational exposure to formaldehyde were recruited into this study. DNA damage levels were measured by comet assay. The polymorphisms of XRCC1 gene were analyzed by polymerase chain reaction(PCR) with restriction fragment length polymorphism(RFLP) method. The multiple covariance analysis was used to compare olive trail moment and comet trail length adjusted confounding factors. RESULTS: In formaldehyde exposed workers, after ages, smoking and drinking status and occupational exposure level were adjusted, means of Olive trail moment and comet trail length in the subjects with variant genotype at Arg280 His site (geometric means 4.30 and 13.42 respectively) were higher than subjects with wild type homozygote (geometric means 3.38 and 11.71 respectively), the differences were significant (Olive trail moment: P < 0.05, comet trail length: P < 0.01) . No associations between the polymorphisms at other three sites in XRCC1 gene and means of olive trail moment and comet trail length in exposure workers were found. CONCLUSION: The polymorphisms of XRCC1 gene may modulate the effects of DNA damages induced by formaldehyde in workers.

[Early genetic effects on workers occupationally exposed to formaldehyde].

OBJECTIVE: To investigate the DNA and chromosome damage in peripheral blood lymphocyte of workers occupationally exposed to formaldehyde (FA). METHODS: All 151 workers occupationally exposed to FA from two plywood factories and 112 workers without occupational FA exposure working in a machine manufactory were recruited into this study. Comet assay and cytokinesis-block micronucleus technique was used to evaluate the DNA and chromosomal damage of peripheral blood lymphocyte. The air FA samples were collected with SKC 224-PCXR8 air samplers. Gas chromatography was used to analyze the FA level. Personal information including occupational history, age, sex, smoking and drinking status was collected by the questionnaire. RESULTS: The time weighted average concentration (TWA) of FA in the working environment of FA-exposed workers (range 0.10 - 7.88 mg/m(3)) was higher than those in controls (< 0.01 mg/m(3)). The olive tail moment (Olive TM) in low FA-exposed workers [3.03 (2.49 - 3.67)] was lower than that in high FA-exposed workers [3.95 (3.53 - 4.43)], but higher than that in controls [0.93 (0.78 - 1.10)], the differences were statistical significant (P < 0.05). Comet trail length in FA-exposed workers were significantly higher than that in controls [6.78 (6.05 - 7.60)], but no significant differences ware found between the high FA-exposed workers [12.59 (11.80 - 13.43)] and the low FA-exposed workers [11.25 (10.12 - 12.50)]. The frequency of micronuclei per 100 binucleated cells in low FA-exposed workers (0.41 +/- 0.25) was lower than that in high FA-exposed workers (0.65 +/- 0.36), but higher than that in controls (0.27 +/- 0.13), the differences were statistical significant (P < 0.05). The increased tendencies with the exposure levels were found in those three indices. In stratification analysis, the same results were found. CONCLUSION: In the current FA exposure levels, the DNA and chromosomal damage in peripheral blood lymphocyte might be induced by FA exposure, and be increased with the levels of exposure.