Study On Toxicity Of Microcystin-lr On Liver, Kidney And Testicle Cells In Male Mice

A lot of algae in fresh water are harmful to human beings.Microcystins(MC) is widely distributed and one of the most harmful toxin.It usually exists in the algae cell. When the algae die,it releases the pollutant to the water environment.One of the most commonly found microcystin variants is microcystin-LR(MC-LR).Liver is the most important target organ of microcystins.Kidney is the secondly important target organ.Microcystins also have heart toxicity,neurotoxicity,stomach and intestine toxicity.Genetoxic is doubtful.Some studies have indicated that microcystins can accumulate in the gonad of the invertebrate,the gonad is regarded as the second target organ of microcystins,and microcystins can be found in the invertebrate's progeny.Animal experiment also has indicated the toxicity effect of microcystins on the male reproductive system of mice,but the research about the toxicity effect of microcystins on the reproductive system is rare,and the study on genetoxic effect of germ cell has not been reported.Till now,the study on oxidative damage of MC is focus on the inhibition of antioxidative system,but it is not enough to evaluate the degree of organism damage. Because the directly oxidative damage can not be revealed,and protein is very important for organism,study on the protein oxidative damage of MC has not been reported.In this study,the male mice were injected intraperitoneally pure microcystins-LR, and then,genetoxic effect and oxidative damage effect of microcystins-LR on liver, kidney and testicle cell were studied to know more about the biological effect of MC.Materials and methods1.Forty-five healthy male KM mice weighted about 30 gram were allocated into 9 groups randomly.There were five mice in every group.The 4 experimental groups were control groups,low-dose MC-LR groups,middle-dose MC-LR groups,and high-dose MC-LR groups(each group is double).The other group was cyclophosphamide group.The dose is 0,3,6,12,30μg/kg·bw,respectively.2.According to the above-mentioned experimental dose,every MC-LR treatment group was intraperitoneally injected with pure MC-LR per day,while the control mice were injected with saline per day,7 days in all.The cyclophosphamide group was intraperitoneally injected once.At the end of the experiment,after putting the mice to death,liver,kidney and testicle were dissected out and weighted for calculating their organic coefficient.The KCl-SDS precipitation method was utilized to detect the DPC(DNA-protein crosslinks) in mice liver,kidney and testicle cell. The micronucleus rate in early stage sperm cells was measured by the micronucleus test.The protein carbonyl content was measured by using spectrophotometric DNPH assay.3.The measuring results were analysed using SPSS 12.0.One-way analysis of variance(ANOVA) and Dunnett-t test were used.The significant level was set at 0.05.Results1.The mice's body weight,liver weight,testicle weight all have no significant difference(P＞0.05),but kidney weight have significant difference(P＜0.05),when low-dose MC-LR group compared with the control group.The mice's body weight, liver weight,kidney weight,testicle weight have significant difference,when middle-dose MC-LR group and high-dose MC-LR group compared with the control group(P＜0.01).Their organic coefficient have no significant difference,when low-dose MC-LR group compared with the control group(P＞0.05).Their organic coefficient have significant difference,when middle-dose MC-LR group and high-dose MC-LR group compared with the control group(P＜0.05 or P＜0.01).2.The DPC coefficient in liver all have significant difference,when low,middle and high-dose MC-LR group compared with the control group(P＜0.05),and the average DPC coefficient value is maximum in the middle-dose MC-LR group.The DPC coefficient in kidney have significant difference,when low-dose MC-LR group and middle-dose MC-LR group compared with the control group(P＜0.05),but has no significant difference,when high-dose MC-LR group compared with the control group(P＞0.05).The DPC coefficient in testicle has no significant difference,when low-dose MC-LR group compared with the control group(P＞0.05),but have significant difference,when middle-dose MC-LR group and high-dose MC-LR group compared with the control group(P＜0.05),and the average DPC coefficient value is maximum in the middle-dose MC-LR group.3.The mieronucleus rate in early stage sperm cells in the low,middle and high-dose MC-LR group are all higher than the micronucleus rate in the control group. Micronucleus rate have no significant difference,when low-dose MC-LR group compared with the control group(P＞0.05),but have significant difference,when middle-dose MC-LR group and high-dose MC-LR group compared with the control group(P＜0.05 or P＜0.01).4.The protein carbonyl content in liver have significant difference,when low, middle and high-dose MC-LR group compared with the control group(P＜0.01).The protein carbonyl content in kidney have significant difference,when low-dose MC-LR group compared with the control group(P＜0.05),and have significant difference,when middle-dose MC-LR group and high-dose MC-LR group compared with the control group(P＜0.01).The protein carbonyl content in testicle have no significant difference,when low-dose MC-LR group compared with the control group (P＞0.05) but have significantly difference,when middle-dose MC-LR group and high-dose MC-LR group compared with the control group(P＜0.01). Conclusions1.The body weight,liver,kidney and testicle weight and their organ coefficient are all related with the MC-LR dosage.2.MC-LR can induce the DPC formation in mice liver,kidney,and testicle cell.3.MC-LR has the potential mutagenie damage effect on the chromosome of the male mice germ cells.4.MC-LR has oxidative damage effect on liver,kidney,and testicle protein.