[Effect of neonatal exposure to environmental pollutants on the DNA methylation of rat testis].
ABSTRACT To investigate the effects of neonatal exposure of DNA methylation inhibitor, Cadmium and PCB153 on DNA methylation, apoptosis and spermatogenesis in SD rats.
Neonatal SD rats were randomly divided into 10 groups and received oral administrations of PCB153 (0.025, 0. 250, 2.500 mg/kg), or Cadmium (1, 2, 4 mg/kg), or positive control 5-Aza-CdR (0.025, 0.250 mg/kg), or vehicle control for five days from PND3. Half of the rats were killed 24 h after the last administration. The remains were fed until 12 weeks. Sperm numbers, apoptosis and DNA methylation levels in testis were investigated.
The daily sperm production was significantly decreased in each neonatal exposed group (P < 0.05). Neonatal rats exposed to 5-Aza-CdR and Cadmium reduced the global DNA methylation level, increased apoptosis, while PCB153 exposure did not significantly change DNA methylation and apoptosis.
Neonatal rats exposed to chemicals could reduce spermatogenesis via multiple pathways. Lower DNA methylation and increased neonatal apoptosis were suggested as one of the causes.