Application Of Caenorhabditis Elegans On Evaluating Arsenic Drug Toxicity And Preparation Of The Kit For Testing Nematode Survival Rate

The toxicity of RBS, As2O3 and AS4S4 was evaluated by C. elegans as a model organism. Several endpoints of LC50, reproduction and development, motility, pharyngeal pumping rate in wild strain N2, nuclear translocation of DAF-16 in mutant strain TJ356, thus got a multi-disciplinary evaluation of toxicity of RBS, As2O3 and AS4S4. Additionally, TTC-formazan assay was first used to measure the live rate of C. elegans, and the conditions on TTC reaction and nematode culture and conservation were optimized for developing a C. elegans survival kit on acute toxicity test.Based on the results of LC50, the order of toxicity was:As4S4>RBS>As2O3. The results demonstrated that the impact of RBS on worm body length was in a dose-dependent manner, and body length of the high concentration group (As content of 12.8μg/mL) was only 56.7% of the control group. No effect of As2O3 and As4S4 was found on body length, and there were no clear differences among different concentrations. The high concentration group of RBS delayed spawning for one day.The inhibitory effects of each drug on head thresh of nematodes were:compared with control group (30.5 times/min), head thresh rate of nematodes exposed to RBS were between 21.1 and 23.0 times/min, nematodes exposed to As2O3 were between 22.5 and 26.1 times/min,and 22.1-31.8 times/min of As4S4.Data from this experiment showed that, the nuclear translocation of DAF-16 of TJ356 happened in nematodes exposed to RBS, As2O3 and As4S4 in a dose-dependent manner. The pumping rate of worms treated with RBS, As2O3 and As4S4 were 66 times/secs,68 times/secs, and 79 times/secs, respectively, and control group was 83 times/secs.The optimum condition of TTC-formazan assay was:temperature at 32℃, concentration of 4% of TTC, and stained for 30 mins. The optimal condition of liquid culture was:inoculation volume of E. coli OP50 was 0.5 g per 15 mL S Medium,1000 worms, cultured at 20℃with speed of 130 rpm. The conservation conditions:10000 worms per mL with ampicillin content of 100μg per mL, which could be stocked at 4℃as long as 30 days.