[Di-(2-ethylhexyl) phthalate increases the DNA methylation level of genomes in the mouse testis].

OBJECTIVE: To investigate the effect of the exposure to di- (2-ethylhexyl) phthalate (DEHP) during pregnancy on the DNA methylation level of genomes in the testis of the offspring in mice.

METHODS: Pregnant KM mice were randomly divided into three groups, normal control, corn oil and DEHP-exposed. Corn oil and DEHP (500 mg/[kg x d]) were administrated respectively from gestation day 12.5 (GD 12.5) to postnatal day 3 (PND 3). The testes of the offspring were excised on PND 7, and their genomic DNA was treated with EcoR I /Msp I and EcoR I /Hpa II. The genome-wide DNA methylation patterns of the CCGG sites were detected by methylation-sensitive amplification polymorphism (MSAP). The samples were electrophoresed in the ABI 3730 DNA sequencer and the results analyzed by the Genescan3.1.

RESULTS: The average incidence of DNA methylation was (34.03 +/- 3.05)% in the DEHP-exposed mice, obviously higher than (28.37 +/- 2.37)% in the normal control and (28.58 2.45)% in the corn oil group, with statistically significant differences (P < 0.05).

CONCLUSION: Exposure to DEHP during pregnancy increases the DNA methylation level of the genome in the testis of the offspring and affects the apparent genetic modification of the genome, which may be one of the important toxicological causes of the lesion in the reproductive system.