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.

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.

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.

[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.