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Objective To investigate the effect of arsenic exposure on learning and memory ability of rats.Methods Fourty- eight weaned SD rats were randomly divided into four groups,12 in each.The control group drank tap water,the other three groups treated with sodium arsenite at doses of 2.72 mg/L,13.6 mg/L and 68 mg/L for 12 weeks.Morris water maze was used to test the spatial learning and memory ability of rats.Arsenic level in the blood and brain was assessed after Morris water maze test.Results Arsenic contents in the blood of arsenic exposed rats were significantly higher than that in control rats(P
ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the antagonism effects of green tea (GT) against microcystin LR (MC-LR) induced hepatotoxicity and nephrotoxicity in mice.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>GT might elevate antioxidant defense system, clean up free radicals, lessen oxidative damages and protect liver and kidney against MC-LR induced toxicity.</p>