Toxicology
Human
Mutagens
Mutagenic agents (agents that cause mutations) have been shown to increase DNA fragmentation. For example, mouse exposure to ethylnitrosourea showed a relationship between dosage of the mutagen and DNA fragmentation (Evenson et al. 1985). Results were similar for mice treated with thiopeta, another mutagen (Evenson et al. 1986). DNA fragmentation remained abnormal for 44 weeks after exposure to triethylenemelamine. (Evenson et al. 1989). Hydroxyurea exposure revealed DNA fragmentation at the highest dose levels at 8 days and the lower doses at 29 days (Evenson and Jost 1993).
Figure 1. The figure above shows dose response curves of %DFI at 8 (•) and 29 (⇓) days after exposure to hydroxyurea (Evenson and Jost 1993).
Sperm cells were obtained at 8 and 29 days after injections containing 0, 25, 50, 100, 200, 400, and 500 mg/kg hydroxyurea for five days. All concentrations of hydroxyurea significantly increased %DFI values except for 25mg/kg dose (Figure 1).