Assessment The Genotoxicitv Of Cadmium, Volatile Oil From Chenonodium Amhrosinides L. And Their Toxicity Mechanisms Using L5178Y

Cd (Cadmium) is an important environmental pollutant. It is classifiedas the seventh of harmful substances that endanger human health by Agency for ToxicSubstances Management Committee (ATSDR). Chenopodium ambrosioides L., aChinese herbal medicine, is mainly used to expel insects, inhibit bacterial andanticancer.Mouse lymphoma cells L5178Y tk+/-3.7.2C are used as the target cells in thisexperiment. Assesment the genotoxicity of the cadmium and the volatile oil fromchenopodium ambrosioides L. by TK gene mutation assay, micronucleus test and singlecell gel electrophoresis. Study the toxicity mechanisms of cadmium by the loss ofheterozygosity.The cadmium concentration is set to0μg/mL,0.25μg/mL,0.50μg/mL,0.75μg/mL,1.00μg/mL, and10μg/mL. Cyclophosphamide (CP) is a positive control. TheTK gene mutation test results showed that: With the increase in the doses of cadmium,relative survival (RS), relative suspension growth (RSG), Relative total growth (RTG)decreased in downward trend, the tk locus mutation frequency significantly increase,The resistant mutant frequency as786.67±17.07(×10-6) when the cadmiumconcentration is1.00μg/mL, is6times that of the negative control. Micronucleus testresults showed that: the micronucleus rate increased with the increase in theconcentration of cadmium, and increased with the processing time. Exposed for4hours,the micronucleus rate is9.93±0.57(‰) with the concentration to1.25μg/mL. Singlecell gel electrophoresis results showed that: tail length, tail area increase with thecadmium concentration increases, the tail length is61.33μm and the tail area is7583.34μm2with the concentration to1.25μg/mL. The loss of heterozygosity analysis found that cadmium induced the tk locus gene deletions of L5178Y cell. And it means thatcadmium has strong toxicity to L5178Y cells, and it can damage cell DNA, inducedpoint mutations and deletions, chromosome breakage. It has strong mutagenicity.The volatile oil from Chenopodium ambrosioides L. concentration is set to0%,0.001%,0.002%,0.004%,0.006%,0.008%,1%DMSO (Dimethyl Sulfoxide, DMSO)acts as the solvent control and10μg/mL of CP is positive control, the TK genemutation test results show that: relative survival rate, relative suspension growth,relative to the total growth rise at first and then decline. The tk locus mutation frequencywas significantly. The resistant mutant frequency with657.07±9.97(×10-6) is five timesthe solvent control group when the concentration is0.008%. Micronucleus test resultsshow that: the micronucleus rate increases with the concentration of volatile oilincreasing. Exposed for4h, the micronucleus rate reached13.34±0.17(‰) when theconcentration is0.004%. Single cell gel electrophoresis showed that: the general trendof the tail area and tail length grow with the volatile oil concentration increases, taillength and tail area is at maximum of85.38μm and8451.48μm2when theconcentration of0.008%. It shows that the wormseed volatile oil has strong cytotoxicityand the toxic dose range is very narrow. The Wormseed volatile oil can damage theDNA of cell, induced point mutations and deletions, chromosome breakage and lowdose showed a strong mutagenic.Compare the three genetic toxicity test methods based on L5178Y cells, we canfind that: TK gene mutation assay, single cell gel electrophoresis is morecomprehensive than the micronucleus test. They can evaluate the genotoxicity fromvarious indicators. TK gene mutation assay, although time-consuming, but it can havefurther analysis of the genetic mechanisms of toxicity by loss of heterozygosity. SingleCell Gel Electrophoresis save time, but we should note that the dead cells will havesome impact on the test results. Micronucleus test is simple and time-saving.