title: Radioprotection by DMSO against the biological effects of incorporated radionuclides in vivo--Comparison with other radioprotectors and evidence for indirect action of Auger electrons.
abstract: Dimethyl sulfoxide (DMSO) was studied for its capacity to protect against the biological effects of chronic irradiation by incorporated radionuclides. Spermatogenesis in mice was used as experimental model and spermatogonial cell survival was the biological endpoint. DMSO was injected intratesticularly 4 h prior to a similar injection of the radiochemical and the spermhead survival determined. Iodine-125 was localized in either the cytoplasm (H125IPDM) or in the DNA (125IUdR) of the testicular cells. Protection was observed against the high-LET type effects of DNA-bound 125I as well as the low-LET effects of cytoplasmically localized 125I with dose modification factors (DMF) of 3.1+/-1.0 and 4.4+/-1.0 respectively. No protection (DMF = 1.1+/-0.1) was observed against the effects of high-LET 5.3 MeV alpha particles of 210Po. The present findings provide supporting evidence that the mechanism responsible for the extreme biological damage caused by DNA-bound Auger emitters is largely radical mediated and therefore indirect in nature.
authors.affiliation: Department of Radiology, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark 07103, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Goddu
authors.forename: V R
authors.initials: VR
authors.lastname: Narra
authors.forename: R S
authors.initials: RS
authors.lastname: Harapanhalli
authors.forename: R W
authors.initials: RW
authors.lastname: Howell
authors.forename: D V
authors.initials: DV
authors.lastname: Rao
mesh_terms: D000818:Animals; D004247:DNA / Q000528:radiation effects; D004249:DNA Damage; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D004307:Dose-Response Relationship, Radiation; D007065:Idoxuridine / Q000378:metabolism; D007457:Iodine Radioisotopes / Q000378:metabolism; D018499:Linear Energy Transfer; D008297:Male; D051379:Mice; D011059:Polonium / Q000378:metabolism; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D013091:Spermatogenesis / Q000187:drug effects / Q000528:radiation effects*; D013093:Spermatogonia / Q000187:drug effects / Q000528:radiation effects*; D013737:Testis / Q000378:metabolism
chemical_list: D007457:Iodine Radioisotopes; D011837:Radiation-Protective Agents; D004247:DNA; D011059:Polonium; D007065:Idoxuridine; D004121:Dimethyl Sulfoxide