title: Effect of low dose ionizing radiation on the murine pericryptal fibroblast sheath: radiation damage in a mesenchymal system in vivo.
abstract: The effect of low dose ionizing radiation from a variety of sources on the murine small intestinal and colonic pericryptal fibroblast sheath (PCFS) has been investigated. Ultrastructural and light microscopic changes seen within 3 hours after radiation resembles the mode of cell death known as apoptosis. The apoptotic index (AI) was shown to rise steadily for 4 hours after irradiation, and then to return to control levels by 10 hours. 137Cs gamma-irradiation over a range of doses from 0-803 cGy caused an increase in AI from control values of 1-2 per cent to a plateau level of approximately 8.5 per cent for doses above 40 cGy. Investigation of the response of the PCFS to doses of 137Cs and 60Co gamma-irradiation and X-irradiation below 40 cGy demonstrated a steady increase with dose in AI. The survival curve for the radiosensitive subpopulation susceptible to death through apoptosis as a consequence of exposure to non-acute doses of radiation has a D0 of 10.6 cGy and an extrapolation number of 2.3.
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000528:radiation effects; D002588:Cesium Radioisotopes; D003037:Cobalt Radioisotopes; D003106:Colon / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005347:Fibroblasts / Q000528:radiation effects; D005720:Gamma Rays; D007421:Intestine, Small / Q000528:radiation effects*; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D014965:X-Rays
chemical_list: D002588:Cesium Radioisotopes; D003037:Cobalt Radioisotopes