Acrylamide Interfere With Spermatogenesis In Rats Preliminary Study Of The Epigenetic Modifications

Background: In a report released in March 2005, the Joint Expert Committee of the UN Food and Agriculture Organization (FAO) and the World Health Organization (WHO) warned that the unintentional contaminant acryiamide in certain foods may be of public health concern since it has been shown to cause cancer and reproductive problems in animals. Committee concluded that, on the basis of tests in animals, cancer was the most important toxic effect of acryiamide and that consumption of foods with this contaminant at current levels of occurrence may be a public health concern. Then National Health Department of China also alerted the public to concern about acryiamide. However, the toxicology of acryiamide is not very clear, especially its molecular mechanism.Objective: select the male Sprague-Dawley rats as the experiment model. Explore the affects of acryiamide on the formation of imprinting during spermatogenesis. In addition, test the methylation pattern of DMR of Igf2 and peg3 in the sperm of the offspring, and observe whether the imprinting alteration was inheritable.Methods: Male Sprague-Dawley rats were selected as experiment model. Male rats were randomly assigned to treated groups and control group gavages with acryiamide saline separately for two weeks. Each male was mated overnight with 2 control females, 35days later, and male rats sacrificed. 1) Observe the change of the body weight and the count of the spermatozoa, after treated with acryiamide. 2) By controlling the time of killing the animals, we gained the different spermatozoa which were in pre-meiosis stage and post-zygotes stage separately when acryiamide were administrated. Isolate DNA from the spermatozoa of the male rats and their F1 generation male rats then bisulphate genomic sequence and analysis the mathylation pattern of DMRs of two imprint gene (Igf₂, peg₃). 3) The total RNA and protein from the testicles were isolated. Test the expression of HDACs by RT-PCR. And use western blotting to test the change of HDAC4 protein.Results: 1) with the increase of acryiamide dose, the number of spermatozoa dropped dramatically(P<0.05). 2) The analysis of methylation patterns for CpG islands of Igf₂ DMR2 showed that some methyl -groups lost in different extent in the sperm from treated groups when taken 35days later. The methylation pattern of peg3 didn't change. 3) The result didn't show that the abnormal imprinting pattern of Igf₂ DMR was inheritable in statistics.4) the expression of HDACl increased slightly; the expression of HDAC4 decreased dramatically and the protein were cleavage.Conclusion: The results showed that acryiamide interfere with the formation of imprinting during spermatogenesis. The study showed the expression of HDAC4 down -regulated and the protein cleavaged, that played a key role in apoptosis. The expression of HDACl up-regulated suggested that acryiamide perhaps influenced the chromosome-modification.