Epigenetic inactivation of LHX6 mediated microcystin-LR induced hepatocarcinogenesis via the Wnt/ß-catenin and P53 signaling pathways.

Microcystins (MCs) have been shown to be carcinogenic by animal and cellular experiments and found to be associated with the development of human hepatocellular carcinoma (HCC) through epidemiological studies. However, the molecular mechanism of microcystin-LR (MC-LR) induced HCC is still unclear. This study is determined to clarify the role and mechanism of LHX6 in MC-LR-induced hepatocarcinogenesis. Using the previously established MC-LR-induced malignant transformation model in L02 cells, we screened out LHX6, homeobox gene that was significantly changed. We found that LHX6 was significantly down-regulated in MC-LR treated L02 cells and the liver tissue of rats treated for 35 weeks with 10 µg/kg body weight of MC-LR. Expression of LHX6 in human tumor tissue was significantly down-regulated in high MC-LR-exposure group. LHX6 was hypermethylated in MC-LR treated L02 cells and up-regulated after treatment with 10 µM of 5-aza-2'-deoxycytidine. Furthermore, overexpression of LHX6 inhibited proliferation, invasion and migration of malignantly transformed L02 cells in vitro and in vivo, while knockdown of LHX6 resulted in an opposite phenotype. In addition, we found that up-regulation of P53 and Bax resulted in apoptosis, and that down-regulation of CTNNB1 and MMP7 led to migration of MC-LR treated L02 cells. Blockade of P53 and CTNNB1 by its inhibitor significantly diminished the effect of LHX6. These genes were working together during the process of MC-LR-induced hepatocarcinogenesis. Our study demonstrated for the first time that LHX6 gene expression is regulated by DNA methylation and can inhibit the proliferation, invasion and migration through Wnt/ß-catenin and P53 signaling pathways during the MC-LR-induced hepatocarcinogenesis. This result may suggest that LHX6 gene can be used as a potential target gene and a biomarker for liver cancer treatment.

Epigenetic silencing of ALX4 regulates microcystin-LR induced hepatocellular carcinoma through the P53 pathway.

Recent studies have shown that microcystin-LR (MC-LR) is one of the principal factors that cause liver cancer. Previously we have found that Aristaless-like Homeobox 4 (ALX4) was differentially expressed in MC-LR-induced malignant transformed L02 cells. However, the expression regulation, role and molecular mechanism of ALX4 during the process of liver cancer induced by MC-LR are still unclear. The expression of ALX4 was detected by quantitative reverse-transcription PCR and Western blot in MC-LR induced malignantly transformed cell and rat models. Methylation status of ALX4 promoter region was evaluated by methylation-specific PCR and bisulfite genomic sequencing. The anti-tumor effects of ALX4 on MC-LR induced liver cancer were identified in vitro and in vivo. ALX4 expression was progressively down-regulated in MC-LR-induced malignantly transformed L02 cells and the MC-LR exposed rat models. ALX4 promoter regions were highly methylated in malignantly transformed cells, while treatment with demethylation agent 5-aza-dC significantly increased ALX4 expression. Functional studies showed that overexpression of ALX4 inhibits cell proliferation, migration, invasion and metastasis in vitro and in vivo, blocks the G1/S phase and promotes the apoptosis. Conversely, knockdown of ALX4 promotes cell proliferation, migration and invasion. Mechanism study found that ALX4 exerts its antitumor function through the P53 pathway, C-MYC and MMP9. More importantly, ALX4 expression level showed a negative relation with serum MC-LR levels in patients with hepatocellular carcinoma. Our results suggested that ALX4 was inactivated by DNA methylation and played a tumor suppressor function through the P53 pathway in MC-LR induced liver cancer.

Gene expression network regulated by DNA methylation and microRNA during microcystin-leucine arginine induced malignant transformation in human hepatocyte L02 cells.

Microcystin (MC) is a cyclic heptapeptide compound which could lead to the development of hepatocellular carcinoma. However, the underlying epigenetic regulation mechanism is largely unknown. In this study, microcystin-LR (L: lysine, R: arginine, MC-LR) was used to induce the malignant transformation of human hepatocyte L02 cell line. The profile of gene expression, microRNA (miRNA) and DNA methylation were detected through high-throughput sequencing. Compared with control group, the expression of 826 genes and 187 miRNAs changed significantly in MC-LR treated group. DNA methylation sequencing analysis showed that 2592 CpG sites differentially methylated in promoter or the coding DNA sequence (CDS) of genes, while DNA methyltransferase 3 alpha (DNMT3a) and DNA methyltransferase 3 beta (DNMT3b) were dramatically up-regulated. Functional analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that significantly changed mRNAs and microRNAs were mainly involved in the formation of cancer, proliferation, invasion, migration and metabolism. MiRNA-mRNA network and mRNA-mRNA network analysis showed that hsa-miR-320a, hsa-miR-331-3p, hsa-miR-26a-5p, hsa-miR-196a-5p, hsa-miR-221-3p, coiled-coil domain containing 180 (CCDC180), melanoma antigen gene family member D1 (MAGED1), membrane spanning 4-domains A7 (MS4A7), hephaestin like 1 (HEPHL1), BH3 (Bcl-2 homology 3)-like motif containing, cell death inducer (BLID), matrix metallopeptidase 13 (MMP13), guanylate binding protein 5 (GBP5), adipogenesis regulatory factor (ADIRF), formin homology 2 domain containing 1 (FHDC1), protein kinase CAMP-dependent type II regulatory subunit beta (PRKAR2B), nodium leak channel, non-selective (NALCN), myosin light chain kinase 3 (MYLK3), epidermal growth factor receptor (EGFR) and zinc finger protein 704 (ZNF704) were key miRNAs and genes in the malignant transformation induced by MC-LR in L02 cells. Moreover, we found that expression of MYLK3, EGFR and ZNF704 were regulated by DNA methylation and miRNAs, and these genes affected the cell cycle and cell division. Our study suggested that characteristic gene alterations regulated by DNA methylation and miRNA could play an important role in environmental MC-LR induced hepatic carcinogenesis.

Upregulated long non-coding RNA LOC90784 promotes cell proliferation and invasion and is associated with poor clinical features in HCC.

A growing amount of literature has indicated that long non-coding RNAs (lncRNAs) are important factors in hepatocellular carcinoma (HCC) progression. However, the significance of lncRNAs in the progression and prognosis of liver cancer is largely unknown. In the present study, upregulated lncRNA LOC90784 was identified through integrative analysis of GSE58043 and GSE55191. Furthermore, associations between LOC90784 expression and the clinicopathological characteristics of patients were analyzed with a validated cohort 1 and the Cancer Genome Atlas (TCGA) cohort 2. We investigated the mechanisms by which this highly expressed lncRNA promotes HCC proliferation, invasion and migration via qRT-PCR, fluorescence in situ hybridization (FISH) staining, siRNA transfection, cell proliferation assays, Transwell and colony formation assays, flow cytometry analysis and Western blot. The results showed that LOC90784 expression levels were significantly higher in HCC cell lines and tissues and mainly localized in the cytoplasm. Knockdown of lncRNA LOC90784 expression inhibited proliferation and induced apoptosis and cell cycle arrest by promoting Bax and repressing CDK4 and Cyclin D1 protein expression; it also inhibited invasion and migration by repressing MMP2 and MMP9 expression in HCC cells. LOC90784 overexpression was associated with poor clinical features in the two cohorts and poor overall survival rates in HCC patients with clear resection margins (R0) in cohort 2. These results indicated that LOC90784 upregulation may be a critical oncogene and potential new biomarker in HCC.

Experimental comparison of the reproductive outcomes and early development of the offspring of rats given five common types of drinking water.

Tap water (unfiltered), filtered tap water and processed bottled water (purified water, artificial mineralized water, or natural water) are now the five most widely consumed types of drinking water in China. However, the constituents (organic chemicals and inorganic ingredients) of the five waters differ, which may cause them to have different long-term health effects on those who drink them, especially sensitive children. In order to determine which type of water among the five waters is the most beneficial regarding reproductive outcomes and the developmental behaviors of offspring, two generations of Sprague-Dawley rats were given these five waters separately, and their reproductive outcomes and the developmental behaviors of their offspring were observed and compared. The results showed that the unfiltered tap water group had the lowest values for the maternal gestation index (MGI) and offspring's learning and memory abilities (OLMA); the lowest offspring survival rate was found in the purified water group; and the highest OLMA were found in the filtered tap water group. Thus, the best reproductive and offspring early developmental outcomes were found in the group that drank filtered tap water, which had the lowest levels of pollutants and the richest minerals. Therefore, thoroughly removing toxic contaminants and retaining the beneficial minerals in drinking water may be important for both pregnant women and children, and the best way to treat water may be with granular activated carbon and ion exchange by copper zinc alloy.

Arsenite exposure altered the expression of NMDA receptor and postsynaptic signaling proteins in rat hippocampus.

Chronic arsenic exposure has an adverse effect on neurobehavioral function. Our previous study demonstrated an elevated arsenic level, ultra-structure changes and reduced NR2A gene expression in hippocampus, and impaired spatial learning in arsenite-exposed rats. The NMDA receptor and the postsynaptic signaling proteins CaMKII, postsynaptic density protein 95 (PSD-95), synaptic Ras GTPase-activating protein (SynGAP) and nuclear activated extracellular-signal regulated kinase (ERK1/2) play important roles in synaptic plasticity, learning and memory. We hypothesized that the above molecular expression changes may contribute to arsenic neurotoxicity. In present study, the expression of NMDA receptor and postsynaptic signaling proteins in hippocampus were evaluated in rats exposed to 0, 2.72, 13.6 and 68 mg/L sodium arsenite for 3 months. Decreased protein expression of NR2A, PSD-95 and p-CaMKII α in the hippocampus of arsenite-exposed rats was observed, while the expression of SynGAP, a negative regulator of Ras-MAPK activity, was increased when compared with the controls. Additionally, decreased p-ERK1/2 activity was found in the hippocampus of arsenite-exposed rats. These data suggest that altered expression of NMDA receptor complex and postsynaptic signaling proteins may explain arsenic-induced neurotoxicity.

[Comparison of organic component and di-n-butyl phthalate between human milk and cow milk products].

OBJECTIVE: To explore types of organic components and pollution level of di-n-butyl phthalate (DBP) between human milk and cow milk products. METHODS: Forty healthy postpartum women with an average age of (27.44 ± 3.43) years old were selected, and a 5 ml sample of breast milk were collected. Four different brands of fresh cow milk and 1 brand of milk powder were randomly selected in the market. A total of 15 samples were collected with 3 from each brand, and the qualitative analysis of types of organic components and quantitative analysis of DBP were conducted by gas-chromatography and mass-spectrometry (GC/MS) method. RESULTS: A total of 176 different types of organic components were detected in 40 samples of human milk (averaged at (10.58 ± 4.16) types per sample); 37 different types were detected in 12 samples of fresh cow milk (averaged at (8.67 ± 1.61) types per sample); while 31 types of organic components were detected in 3 samples of milk powder (averaged at (12.67 ± 0.58) types per sample). It was obvious that the types of organic components in milk powder were significantly higher than the other two groups (t = 2.09, 4.00, P < 0.05). The most frequent organic component in human milk and cow milk was 9-octadecenoic acid (45.00% (18/40) in human milk; 53.33% (8/15) in cow milk). DBP concentrations were (57.78 ± 35.42) µg/L, (20.76 ± 6.60) µg/L and (0.45 ± 0.05) mg/kg (equal to (66.78 ± 7.60) µg/L) in human milk, fresh cow milk and milk powder, respectively. The DBP concentration in fresh cow milk was significantly lower than those in human milk and milk powder (t = 37.02, 46.02, P < 0.05). CONCLUSION: Both human milk and cow milk contain different types of organic pollutants, some of which have toxic effects on reproduction and human development.

Reproductive toxicity in male mice caused by organic extracts in tap water from the Jialing River in Chongqing, China.

BACKGROUND: Recently, male reproductive disturbances caused by organic pollutants have aroused particular public concern about the safety of drinking water. The aim of this study was to investigate the toxicity of organic extracts (OE) in tap water from the source of the Jialing River in China on the reproductive system of male mice. METHODS: Kunming male mice were randomly divided into four groups, which included a solvent control (dimethylsulfoxide), a low-, mid-, and high-dose of OE (12.5, 25, and 50 l/kg bw/day, respectively) treated groups. Mice were administered intraperitoneal injections of OE at different doses for five consecutive days. On the 15th day, after treatments, the mice were sacrificed. RESULTS: The results showed that the number of epididymal sperm in the high OE group was decreased significantly (p<0.05); however, the frequency of sperm abnormalities in all treated groups were increased significantly (p<0.05). In addition, serum testosterone and follicle-stimulating hormone levels in the treated groups were also decreased significantly (p<0.05), and mid- and high-doses of OE resulted in a significant decrease in the activity of acid phosphatase and increased activity of γ-glutamyl transpeptidase (p<0.05). Histological changes were observed in the mid- and high-dose OE-treated groups. CONCLUSIONS: The findings of this study suggest that mid and high doses of OE could disturb the male reproductive system in mice. The potential adverse effects of these compounds on the male reproductive system are worthy of further study.

Identification of microcystins contamination in surface water samples from the Three Gorges Reservoir, China.

Physicochemical and biological parameters related to water quality and microcystins (MCs) contamination in aquatic environment of the Three Gorges Reservoir were investigated in August 2004 and January 2005. A solid-phase extraction method and an HPLC equipped with photodiode array were used for MC-LR detection. A quantitative analysis showed the total MC-LR concentrations of water samples ranged from non-detectable to 0.57 µg L⁻¹ among the seven sampling sites. The highest MC-LR concentration was found at sampling site G (Wushan), which was followed by F (Kaixian), E (Wanzhou), D (Fuling), C (Cuntan), and A (Daxigou). The correlation analysis showed the MC-LR concentration was positively correlated with chlorophyll-a concentration. This result suggests that MC concentration in water can be indirectly estimated by analyzing the chlorophyll-a concentration. Overall, the results of this study suggest that more importance should be placed on monitoring of MC contamination and water quality in the Three Gorges Reservoir to ensure drinking water safety and reduce the potential exposure of people to these health hazards.

[Effect of the influent COD and C/N ratio on phosphorus removal of UCT system].

UCT is deeply influenced by COD and C/N ratios. To check this infection, the UCT system was designed to run at variety of influent COD and C/N ratios. The results show that: when the influent C/N ratio is lower than 15, the high influent concentration of COD increases the proliferation of heterotrophic bacteria and decreases the phenomenon release rate. When the influent C/N ratio is higher than 20, the low influent concentration of TN decreases the proliferation of heterotrophic bacteria, the phenomenon release rate rise with the increase of COD. When the influent concentration of COD is lower than 350 mg/L, the phenomenon of denitrifying phosphorus-uptake is very remarkable. The phenomenon release is remarkable when the influent concentration of COD is higher than 350 mg/L. When the influent concentration of COD is lower than 350 mg/L, the promotion of C/N ratio which in the range of 10-20 is obvious, and the promotion decreases along with the increase of C/N ratio. The removal efficiency of total phosphorus achieve higher than 80% steadily when the influent concentration of COD in the range of 250-450 mg/L even in different influent C/N ratio.

[The antagonistic action of epigallocatechin-3-gallate on microcystin LR-induced oxidative damage on hepatocytes of mice and the expression of cytochrome P450 2E1].

OBJECTIVE: To evaluate the effects of antagonistic action of epigallocatechin-3-gallate (EGCG) on microcystin LR (MC-LR) induced oxidative damage on mice and the expression of cytochrome P450 2E1 (CYP2E1) which was one of phase Iota detoxification enzymes. METHODS: A total of 24 specific pathogen free (SPF) male BALB/c mice were randomly divided into four groups, including control group, MC-LR group, low concentration EGCG group, and high concentration EGCG group. Mice were sacrificed on the 15th day, body weight, and the relative organ weight, liver antioxidant enzyme level and lipid peroxidation product, liver histopathology and CYP2E1 gene and protein expression were detected and analyzed respectively. RESULTS: (1) EGCG could antagonise the liver injury which had been damaged by MC-LR. (2) The malonaldehyde (MDA) level ((2.87 +/- 0.03) nmol/mg prot) and superoxide dismutase (SOD) level ((168.18 +/- 2.86) U/mg prot) in MC-LR group were significantly different when compared with the two EGCG treatment groups (the MDA values of the low and high concentration EGCG group were (2.37 +/- 0.05) nmol/mg prot and (1.44 +/- 0.05) nmol/mg prot, F = 906.63, P < 0.01; the SOD values were (176.55 +/- 2.98) U/mg prot and (184.89 +/- 1.53) U/mg prot, F = 32.32, P < 0.01). (3) MC-LR up-regulated the mRNA and protein expression of CYP2E1 (the mRNA values of MC-LR group and control were 1.41 +/- 0.26, 0.86 +/- 0.13, t = -4.22, P = 0.003; the protein values of MC-LR group and control were 0.24 +/- 0.03, 0.12 +/- 0.02, t = -9.21, P < 0.05). EGCG down-regulated the mRNA (the values of the low and high concentration EGCG group were 1.09 +/- 0.08, 0.99 +/- 0.09, F = 9.03, P = 0.004) and protein expression (the values of the low and high concentration EGCG group were 0.21 +/- 0.03, 0.14 +/- 0.02, F = 24.76, P < 0.05) of CYP2E1 which activated by MC-LR. CONCLUSION: The up-regulation of CYP2E1 which induced by MC-LR was inhibited by EGCG intervention. EGCG might antagonize the oxidation damage of hepatocytes in a certain degree.

Evaluation of ovotoxicity in female mice caused by organic extracts in tap water from Jialing River in Chongqing, China.

BACKGROUND: Recently, toxic effects of widespread organic pollutants have received much attention due to the hazards they pose to female reproductive health. The aim of the present study was to determine the female reproductive toxicity of organic extracts (OE) in tap water from the Jialing River in Chongqing, China. METHODS: In our experiment, Kunming female mice that exhibited normal estrous cycles were randomly divided into 4 groups, which included a control group (OE 0 L/kg bw) as well as low- (OE 12.5 L/kg bw/day), mid- (OE 25 L/kg bw/day), and high-dose (OE 50 L/kg bw/day) groups. Mice were continually administered intraperitoneal injections of OE at different doses for 5 consecutive days. On the 15th and 30th day after treatments, half of the mice were sacrificed separately. RESULTS: The results showed that OE decreased relative ovary weights and prolonged the duration of estrous cycle with concomitant increase in estrous phase. There was a significant decrease in the number of corpora lutea of OE-treated mice, but no significant differences were found in healthy and atretic follicle populations compared to control. Ultrastructure observation regarding granulosa cells of the ovary revealed that OE treatment caused mitochondrial swelling together with endoplasmic reticulum expansion. CONCLUSIONS: All these data indicate that OE could exert adverse effects on the development of ovary and also a slight suppressive effect on reproductive functions.

Effects of arsenic exposure from drinking water on spatial memory, ultra-structures and NMDAR gene expression of hippocampus in rats.

Epidemiological investigations indicate that chronic arsenic exposure can damage neurobehavioral function in children. The present study was aimed to study the effects of arsenic exposure from drinking water on the spatial memory, and hippocampal ultra-structures and N-methyl-d-aspartate receptor (NMDAR) gene expression in rats. Sprague-Dawley rats were assigned to four groups: rats in control group drank regular water, rats in other groups drank water with final arsenic concentration of 2.72 mg/L (group A), 13.6 mg/L (group B) and 68 mg/L (group C), respectively, for 3 months. The levels of arsenic in blood serum and hippocampus were monitored. Rats were tested in Morris water maze (MWM) for memory status. Samples of hippocampus were collected from two rats in each group for transmission electron microscopic study and the detection of NMDAR expression by RT-PCR. The rats in group C showed a significant delay in hidden platform acquisition. Neurons and endothelial cells presented pathological changes and the expression of NR2A was down-regulated in hippocampus in arsenic exposed rats. Our data indicated that arsenic exposure of 68 mg/L caused spatial memory damage, of which the morphological and biochemical bases could be the ultra-structure changes and reduced NR2A expression in hippocampus.

[Long-term drinking purified water may aggravate the inhibition of NMDA expression and spatial learning ability induced by lead on rat].

OBJECTIVE: To compare brain lead accumulation and neurotoxicity induced by lead under drinking purified water and tap water on rat. METHODS: All 104 male weaning SD rats were randomly divided into eight groups, matched-four pairs according to drinking water: tap water, purified water, tap water with lead 50 mg/L(lead acetate water-solution), purified water with lead 50 mg/L, tap water with lead 200 mg/L, purified water with lead 200 mg/L, tap water with lead 800 mg/L. All were fed with normal food and environmental cognitions kept consistent Morris water maze(including Place Navigation, Spatial Probe Test, Visible Platform Trial) was measured to test rat spatial learning at the 12 and 24 week. At the end of the experiment (28 week), rats were killed and the lead of brain and blood was measured by Graphite furnace atomic absorption spectrometric method; the NR1, NR2A, NR2B of NMDAR (N-methyl-D-aspartame receptor) in hippocampus were analyzed by RT-PCR. RESULTS: Under the same lead exposure, no significant differences were observed in blood lead, however, brain lead level showed higher in drinking purified water group than that in tap water group. Expression of NR1, NR2A and NR2B in hippocampus of the rats drinking purified water was lower than those drinking tap water, especially at low lead exposure (50 mg/L) (P < 0.05). In the 24 week Morris water maze, place navigation test's escape latency showed significantly prolonged at the rats drinking purified water as compared with those drinking tap water on the pairs of 50 mg/L and 200 mg/L pb2+ groups (P < 0.05), and the differences occurred in early 1-2 days. CONCLUSION: Compared with drinking tap water, drinking purified water might increase the accumulation of brain lead, lower NR1, NR2A, NR2B expression and delay the spatial learning and memory ability under chronic lead exposure in water.

Reproductive and neurobehavioral outcome of drinking purified water under magnesium deficiency in the rat's diet.

Taking magnesium deficient diet and drinking soft water (including purified water, essentially mineral free) are common consumed in the world. The present study was conducted to assess the potential combined influence of maternal drinking purified water and taking magnesium deficient diet on postnatal development and behavior in the offspring of exposed rats. Sprague-Dawley (SD) rat were assigned to four groups: group 1 fed with control diet (Mg(2+) 0.4 g/kg) and control water (Mg(2+) 12.7 mg/L), group 2 fed with control diet and purified water (Mg(2+) 0.015 mg/L), group 3 fed with magnesium deficient diet (Mg(2+) 0.2 g/kg) and control water, group 4 fed with magnesium deficient diet and purified water from 5 weeks of age of the F0 generation to 3 weeks of the F1 generation, respectively. Reproductive and neurobehavioral parameters were measured. Maternal body weights significantly decreased during treatment (before mating) and lactation periods in the group fed with magnesium deficient diet and purified water. There were no significant differences of the reproductive outcome in the groups. Offspring's body weight, development of reflexes significantly reduced in the group 4. Although it was no significant difference in the four groups, the data showed a trend toward a decreased risk for offspring body weight, neurobehavioral development as follows: group 1>group 2>group 3>group 4. Therefore, purified water cannot obviously affect the reproductive outcome when magnesium is sufficient or half of the estimated average requirement (EAR) in the diet. However, drinking purified water can decrease maternal magnesium level slightly, induce offspring's development retardation, especially when the magnesium deficiency in the diet. Furthermore, magnesium deficiency in the diet (half of the EAR) can produce growth delay and reflex development retardation in F1-offspring. Therefore, drinking purified water should be carefully considered, especially for susceptible population.

Multiwalled carbon nanotubes as adsorbents of solid-phase extraction for determination of polycyclic aromatic hydrocarbons in environmental waters coupled with high-performance liquid chromatography.

Multiwalled carbon nanotubes (MWCNTs) were used as a novel kind of solid-phase extraction adsorbents in this work as well as an analytical method based on MWCNTs solid-phase extraction (SPE) combined with high-performance liquid chromatography (HPLC) was established for the determination of polycyclic aromatic hydrocarbons (PAHs), some of which belong to typical persistent organic pollutants (POPs) owing to their carcinogenicity and endocrine disrupting activity. Several conditions that probably affected the extraction efficiency including the eluent volume, sample flow rate, sample pH and the sample volume were optimized in detail. The characteristic data of analytical performance were determined to investigate the sensitivity and precision of the method, and the method was applied to the determination of PAHs in environmental water samples such as river water sample, tap water sample and wastewater sample from the constructed wetland effluent. The experimental results indicated that there were excellent linear relationship between peak area and the concentration of PAHs over the range of 0.04-100 microg L(-1), and the precisions (RSD) were 1.7-4.8% under the optimal conditions. The detection limits of proposed method for the studied PAHs were 0.005-0.058 microg L(-1) (S/N=3). The recoveries of PAHs spiked in environmental water samples ranged from 78.7 to 118.1%. It was concluded that MWCNTs packed cartridge coupled with HPLC was an excellent alternative for the routine analysis of PAHs at trace level.

[Antagonism effects of green tea against microcystin induced oxidant damage on liver and kidney].

OBJECTIVE: To evaluate the antagonism effects of green tea (GT) against microcystin LR (MC-LR) induced hepatotoxicity and nephrotoxicity in mice. METHODS: All 40 male mice were randomly divided into four groups. Mice in group III and IV were pretreated with green tea for free drink at doses of 2 g/L and 12 g/L prior to MC-LR intoxication, for consecutively 18 days. The toxin treatment mice were administered continually intraperitoneal injections of MC-LR at a dose of 10 microg x kg(-1) x d(-1) bw from day 6th till sacrifice, continually 13 days. Mice were sacrificed and immediately subjected to necropsy, and the body weight, relative organ weight, serum biochemical parameters, antioxidant enzyme levels (SOD and GSH), lipid peroxidation products (MDA) and histopathology were systematically evaluated. RESULTS: MC-LR exposure led to increase the oxidative stress and organ injury was significantly observed through biochemical parameters and microscopic evaluation. However, high dose of GT pretreatment caused a significant elevation in serum GSH and SOD levels, and a decrease of serum MDA level as compared with MC-LR control. The mean values of GSH and SOD activities were separately 467.29 mg/L and 139.22 U/ml in group IV. Subsequently, GT pretreatment obviously diminished the serum ALT, AST and Cr activities. Those pathological damages in liver and kidney, were to a certain extent, lessened in GT pretreatment mice in correlation with the biochemical parameters. CONCLUSION: GT might elevate antioxidant defense system, clean up free radicals, lessen oxidative damages and protect liver and kidney against MC-LR induced toxicity.

Protective effects of green tea polyphenols against subacute hepatotoxicity induced by microcystin-LR in mice.

Green tea polyphenols (GTP) have been shown to possess anti-oxidative, anti-mutagenic and anti-carcinogenic activities. The present study aimed to evaluate the chemopreventive efficacy of GTP against subacute hepatotoxicity induced by microcystin-LR (MC-LR) in mice and also elucidates the underlying mechanisms. In this study, healthy Kunming male mice (24-26gbw) were randomly assigned to five groups. Group I was fed on normal diet and water ad libitum as control. Group II was maintained on normal diet and received MC-LR intraperitoneal injection (10µg/kg/day) from day 6 till sacrifice. Mice in groups III, IV and V were daily pre-treated with GTP through intragastric administration at doses of 50, 100 and 200mg/kg/day from day 0 prior to MC-LR intoxication, consecutively 18 days. The results showed MC-LR alone led to oxidative stress and to damage antioxidant defense system, as evidenced by elevation of serum and liver lipid peroxidation. Additionally, hepatocellular apoptosis and injury were significantly observed. GTP pre-treatment caused a significant elevation in serum antioxidant enzymes GSH and SOD activities as well as a decrease in hepatic lipid peroxidation MDA level and serum ALT, AST, ALP activities. GTP pre-treatment obviously inhibited hepatocellular apoptosis and up-regulated Bcl-2 protein expression. The damages in liver were less severe in GTP pre-treated mice in correlation with the biochemical parameters. In summary, this study confirmed that repeated exposure to MC-LR could induce hepatotoxicity. Our study demonstrated that GTP can reduce MC-LR-induced oxidant stress and prevent biochemical parameters and pathological changes caused by MC-LR in a dose-dependent manner. The results indicated that tea polyphenols have a potential to be developed as a preventive agent against MC-LR-induced toxicity and the mechanism involved in the protection could be due to their antioxidant activities.

[Comparison of perfluorooctane sulfonate and perfluorooctane acid in serum of non-occupational human from Shenyang and Chongqing areas].

OBJECTIVE: The purpose of this investigation was to illustrate the perfluorooctane sulfonate (PFOS) and perfluorooctane acid (PFOA) levels in serum of non-occupational exposure human from Shenyang and Chongqing areas and to compare the distributing character and region difference of PFOS and PFOA in those two region human. METHODS: Sera samples of non-occupational human from Shenyang and Chongqing areas were collected, and the concentration of PFOS and PFOA in serum were measured by High Performance Liquid Chromatography/Mass Selective Detector (HPLC/MS-MIS). RESULTS: The average Shenyang and Chongqing fluorochemical concentrations, respectively, were as follows: PFOS, 22.40 microg/L vs 7.40 microg/L, PFOA, 4.32 microg/L vs 1.00 microg/L. Statistical analysis indicated that serum concentrations of PFOS and PFOA were significantly (P < 0.01) higher in Shenyang human than in Chongqing human. Furthermore, there are sex differences in PFOS and PFOA concentrations in serum at all location. In Shenyang the concentration of PFOS in females were significantly (P < 0.05) higher than in males. The correlations of PFOS (r = 0.298) and PFOA (r = 0.271) with age were significant in females from Chongqing area, and especially the correlations were higher in older females (age t 50) than the groups of age < 13 and 13 - 50 years old. CONCLUSION: This finding suggests that there are predominant regional differences and distributing character for both PFOS and PFOA concentrations in Shenyang and Chongqing areas, and the concentrations of PFOS and PFOA in serum were correlated with age and sex.

[Progress in phthalate ester toxicity in the female reproductive system].

Phthalates are high-production-volume synthetic chemicals with ubiquitous environmental pollution because of their use in plastics and other common consumer products. Epidemiological evidence suggests the relation between women-exposure and the potential health hazards of Phthalates. Here we review research about how phthalates interact with the female reproductive system in vivo, in vitro models, embryo development toxicity and the mechanisms of female toxicity.