title: [The bio-effects of high single-dose radiation on xenografts of Lewis lung carcinoma].
abstract: OBJECTIVE
  To investigate the bio-effects of high single-dose radiation on xenografts of Lewis lung carcinoma.
  
  
  METHODS
  Female 8-week-old C57 mice bearing 4-6 mm diameter Lewis lung carcinoma tumors in the hind legs were divided into 3 groups, control group (0 Gy), high single-dose group (12 Gy/one fraction/day) and routine radiation group (22 Gy/11 fraction/15 d). The mean biological effective dose (BED) of both radiation groups was 26.4 Gy. Changes in hypoxia, DNA damage and cell cycle of the tumor cells at 1, 3, 8, 15 and 21 d after first irradiation was assessed by immunofluorescence and flow-cytometry and the tumor growth curve was also made.
  
  
  RESULTS
  Compared to the fractionated treatment, the tumor growth was delayed after single dose irradiation. The percent of hypoxic cells after single dose radiation was lower than fractioned irradiation at 3, 8, 15 d after first radiation. The foci of gamma-H2AX showed that the single dose caused heavier DNA damages than fractioned irradiation at 1, 3 d after first radiation. The decline of G0/G1 percentage and increase of G2/M percentage of cells was found in both radiation schedules, but the G2/M percentage after single dose radiation was higher.
  
  
  CONCLUSIONS
  In the C57 mice bearing Lewis lung carcinoma, the high single-dose regimen inhibits the tumor growth more than fractioned irradiation. We hypothesized that conversion of high single-dose to BED using the LQ formalism under estimated the in vivo effect of hypofractionated radiation.
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Wan
authors.forename: Jie
authors.initials: J
authors.lastname: Lan
authors.forename: Yong-Shun
authors.initials: YS
authors.lastname: Chen
authors.forename: Jian-Xin
authors.initials: JX
authors.lastname: Xue
authors.forename: Li-Shuai
authors.initials: LS
authors.lastname: Wang
authors.forename: Hai-Xia
authors.initials: HX
authors.lastname: Song
authors.forename: Lei
authors.initials: L
authors.lastname: Deng
authors.forename: Hua
authors.initials: H
authors.lastname: Ling
authors.forename: You
authors.initials: Y
authors.lastname: Lu
mesh_terms: D000818:Animals; D018827:Carcinoma, Lewis Lung / Q000532:radiotherapy*; D002453:Cell Cycle / Q000528:radiation effects; D004249:DNA Damage; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D009368:Neoplasm Transplantation; D011879:Radiotherapy Dosage