The modifying effect of sodium ascorbate on DNA damage and repair after N-methyl-N′-nitro-N-nitrosoguanidine treatment in vivo

A biological reducing agent, sodium ascorbate, was used to modify both the damage induced by N-methyl-N′-nitro-N-nitrosoguanidine to mouse gastric mucosal cell DNA and the repair of that damage $\text{in vivo}$. Freshly-mixed carcinogen and sodium ascorbate enhanced DNA fragmentation as measured by shifts in alkaline sucrose gradient sedimentation profiles whereas incubation of the two compounds for a short period resulted in reduced DNA fragmentation. Furthermore, periodic administration of sodium ascorbate following stomach cell DNA damage with carcinogen inhibited DNA repair.