The Effect of Dimethyl Sulfoxide on the Induction of DNA Double-Strand Breaks in V79-4 Mammalian Cells by Alpha Particles

Abstract

The present study was undertaken to assess the protective effect of dimethyl sulfoxide (DMSO) against the induction and rejoining of DNA double-strand breaks (DSBs) and inactivation of V79-4 Chinese hamster cells by both high- and low-linear energy transfer (LET) radiations. The cells were exposed under aerobic conditions as monolayers to either low-LET photons (60Co gamma rays) or high-LET alpha particles (238Pu) at 277 K. The initial yield of DSBs, determined by elution under nondenaturing conditions, is linearly dependent on dose. When the irradiation was carried out in the presence of DMSO (0-0.6 mol dm-3), the initial yields of DSBs induced by both gamma and alpha-particle irradiation decrease. With gamma irradiation at [DMSO] > 0.6 mol dm-3, a further decrease in the yield of DSBs occurs. DMSO (0.5 mol dm-3) reduces the initial yield of DSBs by 50 +/- 5% and 32 +/- 4% for photons and alpha particles, respectively. DMSO protects more effectively against cellular inactivation and DSB induction at low LET compared with alpha-particle irradiation with protection factors of 1.7 and 1.4, respectively, for survival and 2.0 and 1.5, respectively, for DSBs. After incubation of the irradiated cells for 3 h at 310 K after high-LET irradiation, the residual yield of DSBs is reduced by < 13% when the irradiations were carried out in the presence of 0.5 mol dm-3 DMSO. With gamma irradiation in the presence of 0.5 mol dm-3 DMSO, 90% of the DSBs are rejoined by 3 h incubation at 310 K. Therefore, the nonscavengeable DSBs induced by alpha particles are not significantly rejoined within 3 h, in contrast to rejoining of the majority of the nonscavengeable DSBs induced by gamma irradiation. From comparison of the data on DSBs and survival for alpha-particle irradiation, it is inferred that the severity of damage is reduced by DMSO through minimizing the formation of OH-induced sugar/base modifications in the vicinity of nonscavengeable DSBs.

ROS and ABA Signaling Are Involved in the Growth Stimulation Induced by Low-Dose Gamma Irradiation in Arabidopsis Seedling

“…However, it is unclear whether the ROS level induced by low-dose gamma irradiation functions as signal molecules involved in the radiation-induced hormetic effects in plants. To test this hypothesis, we examined the effects of ROS reduction due to the presence of DMSO, which is used as an efficient ROS scavenger for ionizing radiation, on seedling growth [55,56]. Our results showed that the germination index, primary root length, and fresh weight of the irradiated samples were significantly inhibited or reduced, whereas these growth parameters were not influenced in the nonirradiated samples by the 0.5 % DMSO treatment (Fig.…”

Effect of DMSO on radiation-induced chromosome aberrations analysed by FISH

“…The ability of DMSO to scavenge induced free radicals was described for high and low LET radiation (deLara et al, 1995). Littlefield et al (1988), analysed Incomplete "one-way" aberrations have been allocated as 2At, 2Bt, , 2Ft and 2Gt following the method proposed by Simpson and Savage (1996).…”

Electron-induced single strand break in the nucleotide of 5- and 6-bromouridine. A DFT study

“…Although cellular repair mechanisms are able to fix damaged DNA [5], when the amount of damage exceeds a certain threshold, apoptosis or necrosis is induced [6]. Most but not all of the damage is induced by hydroxyl radicals [7]. Hydrated electrons bound by an energy of ∼3.4 eV [8] are ineffective at damaging DNA [9], which is characterized by an adiabatic electron affinity of * Corresponding author.…”