Factors influencing heterogeneity of radiation-induced DNA-damage measured by the alkaline comet assay.
Radiat Oncol
; 7: 61, 2012 Apr 20.
Article
in En
| MEDLINE
| ID: mdl-22520045
ABSTRACT
BACKGROUND:
To investigate whether different conditions of DNA structure and radiation treatment could modify heterogeneity of response. Additionally to study variance as a potential parameter of heterogeneity for radiosensitivity testing.METHODS:
Two-hundred leukocytes per sample of healthy donors were split into four groups. I Intact chromatin structure; II Nucleoids of histone-depleted DNA; III Nucleoids of histone-depleted DNA with 90 mM DMSO as antioxidant. Response to single (I-III) and twice (IV) irradiation with 4 Gy and repair kinetics were evaluated using %Tail-DNA. Heterogeneity of DNA damage was determined by calculation of variance of DNA-damage (V) and mean variance (Mvar), mutual comparisons were done by one-way analysis of variance (ANOVA).RESULTS:
Heterogeneity of initial DNA-damage (I, 0 min repair) increased without histones (II). Absence of histones was balanced by addition of antioxidants (III). Repair reduced heterogeneity of all samples (with and without irradiation). However double irradiation plus repair led to a higher level of heterogeneity distinguishable from single irradiation and repair in intact cells. Increase of mean DNA damage was associated with a similarly elevated variance of DNA damage (r = +0.88).CONCLUSIONS:
Heterogeneity of DNA-damage can be modified by histone level, antioxidant concentration, repair and radiation dose and was positively correlated with DNA damage. Experimental conditions might be optimized by reducing scatter of comet assay data by repair and antioxidants, potentially allowing better discrimination of small differences. Amount of heterogeneity measured by variance might be an additional useful parameter to characterize radiosensitivity.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Radiation Tolerance
/
DNA Damage
/
DNA
/
Histones
/
Comet Assay
/
Antioxidants
Limits:
Humans
Language:
En
Journal:
Radiat Oncol
Journal subject:
NEOPLASIAS
/
RADIOTERAPIA
Year:
2012
Document type:
Article
Affiliation country:
Alemania