title: Radiosensitivity of mouse skin epithelial cell line established in serum-free culture: an alternative to animal use.
abstract: A cultured line of murine skin epithelial cells was established to investigate the potential use of cultured cells as an alternative to animal use in radiation research. C3Hf/Sed newborn mouse skin cells have been successfully cultured in serum- and Ca(2+)-free medium with no terminal differentiation to keratinized cells. Presently, more than 25 passages have passed with no loss of stem cell capability. The radiosensitivity and repair of sublethal and potentially lethal radiation damages were investigated in this epithelial cell line. The population cell doubling time was 25 +/- 2.9 hr at 37 degrees C. The clonal growth of epithelial cells after irradiation was performed in the serum-free medium in the presence of lethally irradiated skin fibroblasts. Single dose survival curves of exponentially growing epithelial cells were investigated from the seventh to the twenty-third passages, and no significant changes in radiosensitivity and doubling time were found. The confluent epithelial cells also showed an identical sensitivity to radiation. The alpha/beta ratios of survival curves fitted by the linear quadratic model were 6.1 +/- 1.0 and 5.9 +/- 1.3 Gy for cells in exponential and confluent phases, respectively. The survival curve of epithelial cells left in confluence for 8 hr after irradiation showed a smaller beta value than that of cells plated immediately after irradiation with a resultant alpha/beta ratio of 9.5 +/- 3.8 Gy. This alpha/beta ratio was identical to those found in many animal experiments, suggesting a potential use of this cell line as an alternative to animal use. The magnitude of repair of sublethal damage following 6 Gy was greater than that following 3.9 Gy. Survival curves were also obtained following twice-a-day irradiations with no sign of rapid repopulation. These results are discussed by comparing with published in vivo and in vitro data.
authors.affiliation: Department of Radiation Medicine, University of Kentucky Medical Center, Lexington 40536.
authors.forename: H
authors.initials: H
authors.lastname: Maezawa
authors.forename: K H
authors.initials: KH
authors.lastname: Wong
authors.forename: M
authors.initials: M
authors.lastname: Urano
mesh_terms: D000826:Animal Testing Alternatives; D000818:Animals; D002460:Cell Line; D004847:Epithelial Cells; D004848:Epithelium / Q000528:radiation effects; D005260:Female; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D011836:Radiation Tolerance; D012867:Skin / Q000166:cytology / Q000528:radiation effects*